human anatomy. levels of organization cells tissue organ organ system smallest unit of life a...
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Human Anatomy Human Anatomy
Levels of Organization Levels of Organization Cells Tissue Organ Organ
System
Smallest Unit of
Life
A group of cells working together
A group of
tissues working together
A group of
organs working together
4 Types of Body Tissue4 Types of Body TissueMuscle tissue- composed of cells that
contract. ◦Movement is the result of muscle tissues
contracting in a coordinated fashion Nervous tissue- contains cells that
receive and transmit messages in the form of electrical impulses
Epithelial tissue- layers of cells that line or cover all internal and external body surfaces ◦Often provides a protective barrier ◦Your skin is epithelial tissue
4 Types of Body Tissue4 Types of Body TissueConnective tissue- binds, supports,
and protects structures in the body ◦Most abundant and diverse type of
tissue ◦Includes Bone, Cartilage, Tendons,
Fat, and Blood ◦Connects or holds things together,
such as groups of muscles ◦Characterized by large cells that are
embedded in large amounts of an intercellular substance called matrix
Body Systems: (YOU WILL Body Systems: (YOU WILL NEED YOUR BOOK FOR THE NEED YOUR BOOK FOR THE DIAGRAMS)DIAGRAMS)When organs
work together to complete a specific task, it is called an Organ System
There are many organ systems in your body:
◦ Skeletal◦ Circulatory◦ Muscular◦ Respiratory◦ Integumentary(skin)◦ Reproductive◦ Digestive◦ Endocrine◦ Immune◦ Excretory◦ Nervous
Body Cavities (p. 910)Body Cavities (p. 910)When discussing organ systems, many of them
are located in “compartments” in the body called cavities.◦ Cranial cavity: contains the brain◦ Spinal cavity: surrounds the spinal chord◦ Thoracic cavity: contains heart, lungs and
organs of the respiratory system◦ Abdominal cavity: contains organs of
digestive system Diaphragm: separates abdominal and
thoracic cavity◦ Pelvic cavity: contains organs of
reproduction and excretion
Skeletal Skeletal This system
provides support for the entire body
Ribs protects our vital organs-like your heart and lungs
The spine is the central support for the body.
The longest bone in your body is your femur
Skeletal Skeletal Your hands and
feet are so flexible because they are made of MANY bones:◦ Each foot has 26
bones, while each hand has 27 bones
◦ That means that over half your bones are found in your hands and feet!!!
Skeletal (p.911) Skeletal (p.911) Axial Skeleton
◦skull, rib cage, spine (backbone), sternum
Appendicular Skeleton◦arms, legs,
pelvis, scapula, and clavicle (shaded in on picture)
Joints (p. 915) Joints (p. 915) The place where two bones
meet is called a jointFixed joints: prevent
movement. Often connective tissue is located in a fixed joint to absorb impact.Example: skull
Semimovable joints: give limited movement. Generally allow enough movement to absorb shock or impactExample: spinal chord
Moveable joints: allow a wide range of motion.Example: knees,
shoulders
Joints (p. 916)Joints (p. 916) Joints that are subject to a lot of
pressure (like your knees) are cushioned and protected from friction (which would damage the bones) by cartilage and synovial fluid (also called synovial sac). They connect to the bone with ligaments◦ Cartilage: connective tissue
located between moveable bones. Acts as a surface to reduce friction and wear.
◦ Ligaments: tough connective tissue that hold the bones of a joint in place
◦ Synovial fluid : fluid secreted that lubricates the bones of the joint to reduce friction and wear
JointsJointsTwo painful conditions can
exist at the joints:◦Rheumatoid arthritis:
immune system attacks the body at the joints. Causes inflammation, swelling and stiff joints
◦Osteoarthritis: cartilage begins to wear thin. The bones begin to rub together and causes severe discomfort
Bone anatomy (p. 912) Bone anatomy (p. 912) While your bones are hard
on the outside (compact bone and periosteum), they are soft on the inside (spongy bone).◦ Periosteum: tough
membrane that covers the surface of the bone (where a lot of nerves are)
◦ Compact bone: located beneath the periosteum.
You’re hard bone is stronger and lighter than steel!!
Bone anatomy (p.912) Bone anatomy (p.912) Beneath compact bone is an area of
connective tissue called spongy bone or soft tissue called bone marrow.◦ Spongy bone: strong bone
lattice that is located at points of physical stress
◦ Bone marrow: serves as a production center for blood cells or an energy reserve Red bone marrow: produces
red blood cells, white blood cells, platelets (blood cells don’t have nuclei to perform mitosis)
Yellow bone marrow: mostly fat cells that serve as an energy reserve
Internal structure of compact Internal structure of compact bone (p. 913) bone (p. 913)
The structure of bone material◦Bone is made primarily of cylindrical pieces
made of mineral and protein called lamellae When young, your bones are made of cartilage
that eventually harden to bone (ossification)
◦In the central cylinder of the lamella is a channel called the Haversian canal These channels are where the blood vessels
bring nourishment and carry away wastes.
◦Surrounding each Haversian canal is a layer of proteins and bone cells (osteocytes)
Muscular Muscular
Muscles are responsible for your body's every move.
There are 3 types of muscles:◦Skeletal◦Smooth ◦Cardiac
Skeletal MuscleSkeletal MuscleSkeletal muscles move and support the
skeleton.There are 640 individually named skeletal
muscles. When these muscles contract or shorten,
your bone moves. Skeletal muscles are voluntary muscles
(which means we can consciously control them)
Composition of skeletal Composition of skeletal muscle (p. 919)muscle (p. 919)
Skeletal muscle is made of cells called muscle fibers◦Muscle fibers have many nuclei and are
separated by bands called striationsMuscle fibers are gathered in groups
called fasciclesMuscle fibers are made of the
following:◦Myofibrils◦Myosin◦Actin
Composition of skeletal Composition of skeletal muscle (p. 920)muscle (p. 920)
Myofibrils are threadlike structures that make up a muscle fiber◦They are made of 2 proteins that enable
a muscle to contract Myosin: Thick protein fibers that mesh with
actin proteins Actin: Thin protein fibers that overlap with
myosin proteins Each actin-myosin bundle is bordered by an
area called a Z line. This region from one Z line to the next is
called a sarcomere
Contraction of muscleContraction of muscleThere is a “head” on myosin that fits into “grooves”
created by actinWhen a muscle contracts the myosin “head” pulls
the actin strand and shortens itThe “head” can then move to another “groove” in
the actin to continue to shorten the actin strandThis process requires ATP If you work out hard, you don’t have enough oxygen
to go through the Kreb’s cycle . . . oxygen debt◦ Your muscles begin to run out of ATP (muscle
fatigue)◦ You must go through lactic acid fermentation (this
is why your muscles get sore . . . lactic acid build up)
Contraction of muscle (p. Contraction of muscle (p. 921)921)Most muscle are arranged as
opposite pairsMuscles always pull bones, not push
them so you need to be able to contract in two different directions◦Flexor bends the joint to flex the limb
(biceps pull your arm in)◦Extensor flexes to straighten the limb
(triceps allow you to straighten your arm)
Connectors (p. 916)Connectors (p. 916)Ligaments-connect bone to bone
Tendons-connect muscle to bone◦Origin: where a muscle attaches to
a stationary bone◦Insertions: a muscle attaches to a
mobile bone
Smooth MuscleSmooth Muscle Smooth muscles are found in the hollow parts of the body.
◦ They are composed of interlacing sheets of muscle cells. Unlike skeletal muscle, they have a single nucleus.
◦ There are no striations in smooth muscle (no severe contractions)
◦ This would be in places like the lining or the stomach (moves food), intestines (moves waste), blood vessels (change the diameter) and the bladder (moves urine).
◦ A smooth muscle is an involuntary muscle (This means that you cannot consciously control this muscle-they just work when needed)
◦ They move things through the body with a wave-like motion (peristalsis)
Cardiac MuscleCardiac Muscle Cardiac muscle makes up the heart (along with blood
vessels) that makes up the cardiovascular system Cardiac muscles contract automatically to squeeze
the walls of the heart inward.◦ They are similar to both skeletal and smooth
muscle. They are striated (so they can contract) They have a single nuclei They are involuntary
◦ The heart beats nonstop about 100,000 times each day.
◦ Cardiac muscles don’t get tired-they work constantly until you die
Integumentary Integumentary This system
includes skin, hair, nails, and various glands
The function of this system is protection-it is a barrier from injury and infection
The glands are responsible for secreting sweat and oils to release waste or cool the body
Subcutaneous layer
Epidermis (p. 925)Epidermis (p. 925)The epidermis is the outermost layer of skin
◦It is composed of an outer (corneal layer) and a lower (basal) layer
◦This outer layer is made mostly of dead skin cells filled with a protein called keratin This makes skin tough and leathery to resist
the outer environment. It also acts as water-proofing
◦Skin color for the epidermis is controlled by the amount of melanin (a brown pigment) Melanin is produced in the dermis
Dermis (p. 925)Dermis (p. 925)Inner layer of the skin composed of living cells and
specialized structures◦Blood vessels◦Sensory neurons◦Hair follicles (hair is made of dead cells filled
with keratin. Oil from glands keep them supple)◦Glands
Sweat glands to cool the body Oil glands to soften skin, prevent water loss,
etc Because the glands produce sweat, the dermis
is responsible for temperature regulation
Subcutaneous layerSubcutaneous layer
A fatty layer beneath the dermis that acts as insulation and storage of energy (fat cells)
CirculatoryCirculatoryThe circulatory
system is made up of the vessels and the muscles that help and control the flow of fluid around the body.
It consists of the cardiovascular system and the lymphatic system
As blood begins to circulate, it heads from the lungs to the heart
CirculatoryCirculatoryCardiovascular
system◦ Heart◦ Blood vessels◦ Blood
Lymphatic system◦ Lymph nodes◦ Lymph vessels◦ Lymph
HeartHeartThe center of the cardiovascular
system is the heartA septum (wall) separates the
heart into 2 sections◦Right side: pumps blood to the lungs (oxygen deficient blood)
◦Left side: pumps blood from the heart to the rest of the body (oxygen rich blood)
HeartHeartEach side of the heart is separated
into an upper and lower chamber◦Each upper chamber is called an atrium You have a left atrium and right atrium (depends on what side of the septum you are)
◦Each lower chamber is called a ventricle You have a left and right ventricle
Movement of bloodMovement of bloodTo control the flow of blood, you
have flaps ( called valves)that only open in one direction◦The valve that controls blood flow
from the right atrium to the right ventricle is called the tricuspid valve
◦The valve that controls blood flow from the left atrium to the left ventricle is called the mithral valve
Blood flow – Part 1 (p. Blood flow – Part 1 (p. 934)934)Deoxygenated blood enters the right
atrium through a vessel called the vena cava◦Superior vena cava comes from above
the heart◦Inferior vena cava comes from below the
heartRight atrium sends the deoxygenated
blood to the right ventricleRight ventricle contracts and sends the
blood through the pulmonary arteries to the lungs
Blood flow – Part 2 (p. Blood flow – Part 2 (p. 934)934)The deoxygenated blood gains oxygen in
the lungs (discussed in the respiratory system)
Oxygenated blood returns to the left atrium through the pulmonary veins
Oxygenated blood is pumped into the left ventricle
Contraction of the left ventricle forces blood up through a large blood vessel called the aorta
The blood is then transported to the rest of the body
CirculatoryCirculatoryIt leaves the
heart from the left ventricle and goes into the aorta.
The aorta is the largest artery in the body.
The blood leaving the aorta is full of oxygen
Blood vesselsBlood vesselsThere are 3 primary blood vessels in the
circulatory system◦ Arteries: largest of the muscular vessels
that carry blood away from the heart Made of several arterioles
◦ Veins: vessels that contain several valves that bring blood to the heart Made of several venules Vericose veins are caused by poor valves
◦ Capillaries: very small blood vessel where gases (ie. oxygen) can diffuse to the body tissues surrounding the capillary.
Blood Vessels: Blood Vessels: Lumen = Lumen = cavitycavity
CirculatoryCirculatoryThe oxygen rich blood travels
throughout the body through arteries◦Arteries are tough, elastic tubes
that carry blood away from the heart.
◦Arteries branch into capillaries(which are the smallest blood vessels with walls only one cells thick)
CirculatoryCirculatory Much of the
gas/nutrient exchange between the blood and body cells occurs in the Capillaries, which eventually lead to veins◦ Body cells get
oxygen from the red blood cells, then give them carbon dioxide (a waste product)
Veins carry the blood to the heart.
Once the blood reaches the heart, it is pumped back into the lungs to expel the carbon dioxide and obtain oxygen
Diseases of the circulatory Diseases of the circulatory systemsystemHypertension: also known as “high blood
pressure”.◦ This places stress on the walls of arteries and run
the risk that blood vessels will burst Stroke can be caused by a burst blood vessel in
the brainHypotension: also known as “low blood pressure”.
◦ Often feels cold because blood is not able to reach the extremities efficiently
Atherosclerosis: when an artery is blocked by a build up of fatty material◦ Increases blood pressure and can lead to a burst
blood vessel
Lymphatic system (p.939)Lymphatic system (p.939)Part of the circulatory system, the lymphatic system
is responsible for returning fluids (lymph) that have collected in the blood stream
Important differences◦ Lymphatic system is one way (not a circuit)◦ There is no pump (like the heart)
Skeletal muscles squeeze fluid through vessels similar to blood vessels
◦ Lymph passes through lymph nodes that act as filters to remove foreign particles, microorganisms or other tissue debris Lymph nodes have specialized cells called
lymphocytes (specialized white blood cells that fight disease and infection)
BloodBloodBlood is made of many different fluids and cell
types◦ Plasma: yellowish fluid that contains about
90% water and many nutrients, wastes, chemical messengers, etc
◦ Red blood cells : (erythrocytes): oxygen binds to the hemoglobin molecule in red blood cells in the lungs. When they reach the cells in body tissues, they give up the oxygen to the cells and pick up carbon dioxide waste through another gas exchange. Hemoglobin: an iron containing protein on
red blood cells
BloodBloodWhite blood cells (leukocytes): cells of the
immune system used to fight disease and infection◦ Phagocyte: white blood cell that engulfs
infectious cells (ie bacteria) and destroys them◦ Antibodies: produced by another white blood cell
that detects infections cells and activates the bodies immune system Antibodies detect different protein markers on red blood
cells. These proteins give us our blood type (A, B, AB, O). If you don’t have an A or B on your red blood cell, your immune system will attack foreign blood with those “antigens”.
Platelets: fragments of larger cells that can bind together at the site of tissue damage (this is what forms a scab)
Respiratory (p. 947)Respiratory (p. 947)The respiratory
system allows us to breathe
The diaphragm is a muscle contracts and relaxes to move air in and out of your lungs
The lungs are the actual site of gas exchange.
Air Pathway (p. 947)Air Pathway (p. 947)Breathing begins at the nose and
mouth◦Small hairs in the nose, mucous, and a
nasal cavity lined with cilia trap many particulates that are swept into the throat to be swallowed.
The air moves to the pharynx, a tube at the back of the nasal cavity and mouth◦The epiglottis is a flap of cartilage that
can close or open. This prevents food particles from going into the lungs
RespiratoryRespiratoryThe nasal cavity and
throat filter, moisten and warm the air we breathe in
Some of the epithelial tissue that line this system has cilia which trap particles that don’t belong and send them up for you to cough out
Some of the cells produce mucous
Air Pathway (p. 947)Air Pathway (p. 947)The air continues down the pharynx to the
trachea, a rigid pipe made of cartilage◦This is again lined with cilia to trap
unwanted particlesThe trachea branches into 2 bronchi made
of smooth muscle and cartilage◦These are also lined with cilia
The bronchi then separate into several tubes in the lungs called bronchioles◦At the end of these bronchioles are
several aveoli. This is what oxygen and carbon dioxide are exchange.
Respiratory (p. 947)Respiratory (p. 947)The trachea joins
the nasal passage and throat to the lungs.
The bottom of the trachea splits into two branches called bronchi. ◦One enters the
right lung and one goes to the left lung.
◦Aveoli are at the end of the bronchi.
Respiratory (p. 947)Respiratory (p. 947)The bronchial
tree's job is to spread the air from the trachea over a very wide area as quickly as possible.
The air travels until it hits little bags called alveoli, where oxygen is absorbed into the blood stream through capillaries and CO2 is released.
Immune Immune The immune
system defends people against pathogens, or any invader in your body.
Through a series of steps called the immune response, the immune system attacks organisms and substances that invade our systems and cause disease.
ImmuneImmuneBefore you are infected by a disease, your body has a first line of defense◦The skin serves as a physical barrier to outside pathogens
◦Mucous membranes secrete mucous which traps pathogens which can be expelled or destroyed by the acid in your stomach
◦Digestive acids in your stomach
Immune Immune Many of the symptoms you feel when you
are sick are the result of your body fighting invaders:◦Lymph nodes swell when your sick
because they are producing more white blood cells
◦Your fever is meant to slow the growth and reproduction of pathogens (invaders) However a fever over 103°F can
denature your proteins◦Mucous secretions and coughing expel
pathogens
ImmuneImmune If a pathogen gets through your first line of
defense, you have another level of protection . . . nonspecific immune response◦ If your body is damaged (cut or other break in
the skin), your body will start an inflammatory response Blood and lymph go to the area of injury
Histamine is released to attract other cells of the immune system, allow more fluids to the area (causes swelling) and begins the blood clotting process with platelets
White blood cells called phagocytes come in and destroy all pathogens and foreign material
ImmuneImmuneYour last line of defense against
pathogens is the immune system (specific immunity)◦This is a specific response aimed at a
specific infection◦This is not an immediate response (this
is why there is a delay between begin exposed to the disease and showing symptoms)
◦The immune cells of the immune system are called lymphocytes or leukocytes
Immune Immune The cells that are
part of this defense system are white blood cells, or leukocytes.
Leukocytes are produced or stored in many locations throughout the body, including the thymus, spleen, lymph nodes and bone marrow.
Immune Immune The immune
system has it’s own transportation vessels which are a part of the circulatory system◦ They are called the
Lymphatic Vessels◦ Lymph fluid can also
travel in the blood vessels
Immune CellsImmune CellsB cells
◦ Made and developed in the bone marrow
◦ Produce antibodies that recognize antigens (any substance that the immune system believes is foreign to the body)
T cells◦ Made in the bone
marrow and developed in the thymus
◦ Helper T cells recognize part of the antigen on the surface of macrophages They call in cytotoxic T
cells
◦ Cytotoxic T cells destroy cells
CELL-MEDIATED IMMUNITYCELL-MEDIATED IMMUNITYBefore an immune response can begin, it must
be activatedIn a cell-mediated immune response, a
macrophage (specialized white blood cell that ingests pathogens) will engulf a foreign substance and present an antigen on its surface
Receptor proteins on T helper cells bind with the antigen and this causes the macrophage to release a substance called interleukin-1 (IL-1)
IL-1 activates the T helper cell and the T helper cell releases a substance called interleukin-2 (IL-2)
CELL-MEDIATED IMMUNITYCELL-MEDIATED IMMUNITYIL-2 stimulates the production of more
T helper cells and activates T cytotoxic cells
The T cytotoxic cells kill all your cells that have the foreign antigen◦Cytotoxic cells destroy your infected cells
and cancer cellsA third type of cell, T suppressor cells are thought to be responsible for shutting down the cell-mediated immune response
HUMORAL IMMUNE HUMORAL IMMUNE RESPONSE –START HERERESPONSE –START HEREThe release of interleukin-2 (IL-2) from the
cell-mediated response also activates B cells
B cells begin to produce antibodies◦B cells that produce antibodies are called plasma cells
◦Antibodies are proteins that specifically bind to the antigen
◦Antibodies work by binding to foreign substances so that macrophages can come in and destroy them, or
◦Inactivate foreign toxins or viruses
HUMORAL IMMUNE HUMORAL IMMUNE RESPONSERESPONSEThe first time that your body responds to an
infection/disease is called a primary immune response◦ It takes your body about a week to build up
enough of an immune response to fight it off (this is when you feel sick)
If you are exposed to an infection/disease again, your body mounts a secondary immune response◦ After a primary immune response, some of your
plasma cells become memory cells that will recognize the foreign antigen
◦ Secondary immune response only takes a few hours (This is why they say you are immune to a disease. The response is so quick you don’t get sick)
VACCINATIONSVACCINATIONSHow do vaccines work?
◦You are injecting just the plasma membrane/cell wall of a pathogen, or
◦An attenuated pathogen (one that has been rendered inactive by heat, but still has the membrane proteins) Your body will create memory cells to those membrane proteins and you will be mounting a very rapid secondary immune response if exposed to the disease again.
PROBLEMS WITH THE PROBLEMS WITH THE IMMUNE SYSTEMIMMUNE SYSTEM
Allergies: a physical response to a common foreign antigen (pet dander, pollen, etc)
Asthma: a foreign antigen causes the respiratory bronchioles to over-react and narrow (reduced airflow)
Autoimmune disease: your immune cells recognize some part of your body as foreign. This causes your immune system to destroy part of your own body
HIV: destroys the cell-mediated immunity of your body. HIV doesn’t kill you. It’s an infection you get after HIV has destroyed your defenses
Gastrointestinal tractGastrointestinal tractThe gastrointestinal tract, or
digestive tract, is responsible for ingesting and breaking down nutrients to be used by the body
It starts at the mouth and ends with the anus
The following is a breakdown of the digestive tract
Digestive SystemDigestive SystemMOUTH
ESOPHAGUS
LIVERSTOMACH
GALL BLADDER PANCREAS
LARGE INTESTINE
SMALL INTESTINE
APPENDIX RECTUM
ANUS
DigestiveDigestive
The food we eat must be broken down into chemicals that the body can use. ◦This whole process is called digestion and that is the function of the digestive system.
DigestiveDigestiveThe first step takes place
in your mouth, where food is broken down into smaller pieces by the mechanical action of your teeth
Your saliva also contains an enzyme, salivary amylase, that breaks down starch (a type of sugar) into simpler sugars
Digestive Digestive After being swallowed,
the food travels down your pharynx to your esophagus, which is about 10 inches long.Since both air and
food travel down the pharynx, a flap of tissue called the epiglottis prevents food from going down the trachea
The esophagus is covered in muscles that push the food to your stomach.
ESOPHAGUS
DigestiveDigestiveThe stomach releases
acids and enzymes that break down the food◦The stomach has
several layers of smooth muscle that aid in the mechanical digestion of food.
◦The stomach also releases gastric fluids to aid in chemical digestion
STOMACH
DigestiveDigestiveAfter food enters the stomach from the
esophagus, the cardiac sphincter closes to prevent food and gastric juices from entering the esophagus◦Food remains in the stomach for 3-4 hours
The smooth muscles of the stomach churn the stomach to mix the food with the gastric juices and form chyme◦Pepsin is a digestive enzyme that works
at low pH◦HCl is the acid released into the stomach
to make sure the pepsin is active
DigestiveDigestiveWhen digestion is finish, the
stomach forces the chyme into the small intestine through the action of peristalsis, wave-like muscle contractions that cause the substance to move
Once in the small intestine, the pyloric sphincter closes to prevent the chyme from returning to the stomach
DigestiveDigestiveThe small intestine is the
final place for digestion It is about twenty feet long
and one inch in diameter. It is made of 3 parts:DuodenumJejunumIleum
It releases more chemicals to break down food
This is also where the nutrients from food are absorbed through small finger-like projections called villi
SMALL INTESTINE
DigestiveDigestiveWaste products and
food that are not absorbed in the small intestine pass into the large intestine (or colon) through perstalsis
The large intestine is only 5 feet long, but is much wider than the small intestine
LARGE INTESTINE
DigestiveDigestiveThe large intestine
removes water from the food waste to create feces
A meal may take up to three days to pass through your digestive system. It spends about three hours in your stomach and up to 20 hours in your large intestine!
Digestive Digestive The pancreas is an elongated
gland that is below the stomach. It has many functions:◦ It releases hormones to control
blood sugar (ENDOCRINE)◦ It can release sodium
bicarbonate to neutralize the stomach acid before chyme enters the small intestine (DIGESTIVE)
◦ Produces many enzymes that help to break down proteins, carbohydrates, lipids and nucleic acids (DIGESTIVE) PANCREAS
Digestive Digestive The Liver :
Stores glucose as glycogen (DIGESTIVE)
Breaks down toxic substances, bacteria and old blood cells (EXCRETORY)
Secretes bile which is necessary to digest lipids/fats (DIGESTIVE)
The extra bile from the liver is stored in the Gall Bladder (DIGESTIVE)
LIVER
GALL BLADDER
Excretory systemExcretory systemWe’ve already discussed how waste
is removed form the gastrointestinal tract through the large intestine and anus
The other major way to remove waste is through the urinary system◦Kidneys◦Ureter◦Urinary bladder◦Urethra
KidneysKidneysResponsible for removing most of
the nitrogenous wastes◦Most nitrogenous waste first goes to
the liver in the form of ammonia◦Ammonia is extremely toxic so the
liver converts into the less toxic chemical urea
Urea is sent into the blood stream where it enters the kidneys for disposal
Excretory – SEE p. 994Excretory – SEE p. 994The kidney is made of several units called
nephrons◦Nephrons are tiny tubes that end in a tight
ball of capillaries called Bowman’s capsule◦The purpose of the nephrons is to filter the
bloodBlood first enters Bowman’s capsule where
nutrients in the blood are reabsorbed while the waste is allowed to pass
The blood continues to flow through the nephron and continues to filter out nutrients and allow the waste to pass
ExcretoryExcretoryThe nutrients reabsorbed during the
filtration process are returned to the bodyThe fluid and waste that remain form
urine and are transported to the ureter, a narrow collecting tube attached to the kidney
Each ureter leads to a storage organ called the urinary bladder
When the waste is ready to be evacuated, muscular contractions force the urine out through a tube called the urethra
Other avenues of Other avenues of excretionexcretionIn addition to excretion through the gastrointestinal tract and urinary system, we have already discussed other avenues of waste removal:◦Lungs: removes CO2
◦Skin: removes wastes, salts and oils in the subcutaneous layer
Nervous Nervous The nervous system is divided
into two main systems:◦The central nervous system (CNS) ◦The peripheral nervous system
Central Nervous SystemCentral Nervous SystemThe spinal cord and the brain
make up the CNS. Its main job is to get the
information from the body and send out instructions.
Central Nervous SystemCentral Nervous SystemThe brain helps to control all of the
body systems and organs, keeping them working like they should. ◦The brain communicates with the rest of the
body through the spinal cord and the nerves.
◦This system also gives instructions to all parts of the body about what to do and when to do it
◦Reflexes are involuntary, self protective movements and are not controlled by your brain (they just go to spinal cord and back)
Anatomy of the brainAnatomy of the brainThe brain is composed of 4 basic parts
◦Cerebrum: The cerebrum is responsible for higher levels of thinking and communication Speech, reasoning
◦Diencephalon: This is the relay center for the brain where information entering or leaving the brain is routed
◦Brain stem: This is responsible for a lot of involuntary responses in the body Heart rate, homeostasis, respiration, sensory
input
◦Cerebellum: Helps to coordinate movement
Spinal cordSpinal cordThe spinal cord is the central
relay between the brain and the rest of the body◦A flexible spine gives protection to
the nervous tissue that makes up the spinal cord
◦Signals are both sent are received via the spinal cord
Peripheral Nervous Peripheral Nervous SystemSystemThe peripheral
nervous system is made up of all of the nerves and the wiring.
This system SENDS the messages from the brain to the rest of the body as electrical signals.
Peripheral Nervous Peripheral Nervous SystemSystemCells of the nervous system are called
neurons◦ Neurons carry messages in the form of an
electrical impulses. ◦ The messages move from one neuron to
another to keep the body functioning. ◦ Unlike other body tissues, nerve cells
cannot also be repaired if damaged due to injury or disease.
Structure of neuronStructure of neuronThe cell body contains the
organelles and nucleus of the cell◦Dendrites are structures that
receive signals from other neurons◦Axons are used to transmit signals
away from nerve
Structure of neuronStructure of neuronThe axon of the neuron is covered in a lipid
layer known as the myelin sheath◦The myelin sheath acts as an insulator
like a rubber cordSchwann cells surround the axon and are
responsible for making the myelin sheath◦Gaps in the myelin sheath are known as nodes of Ranvier
Axons end in an axon terminal with a gap between the next neuron known as a synapse
How do neurons work?How do neurons work?Nerves send signals in the form of
an action potential◦All neurons contain an electrical charge
inside the cell that is different than outside. This difference in charge is called a membrane potential
◦When the charge is changed (by allowing ions into or out of the membrane), you can move a charge along the nerve Change the potential in different spots
How do neurons work?How do neurons work?Resting potential
◦ When the neuron is not sending or receiving a signal, there are more negatively charged proteins and potassium ions, K+, inside the cell and more sodium ions, Na+ outside the cell . . . net negative charge
Action potential◦ When a signal is sent along the neuron, ion
channels allow the sodium ions into the cell (via a concentration gradient) through a sodium channel (facilitated diffusion) . . . net positive charge
◦ This changes the charge of the cell and the signal causes the next cell in line to start an action potential
How do neurons work?How do neurons work?After the action potential, the cell
needs to regain its state of resting potential◦To do this it utilizes the sodium-potassium pump to pump the sodium out of the cell Active transport using ATP
◦During this time, the nerve cannot send another signal and is called the refractory period
Sending a signal between Sending a signal between neuronsneuronsA neuron can only send a signal to
another neuron through the synapseTo do this, a neurotransmitter called
acetylcholine is released from the axon terminal
Acetylcholine travels across the neuron and stimulates the next neuron, muscle or organ that needs to receive the signal
After the acetylcholine has sent the signal, an enzyme called acetylcholine esterase breaks down the acetylcholine
AcetylcholineAcetylcholine
Somatic vs. Autonomic Nervous Somatic vs. Autonomic Nervous System (Peripheral Nervous System (Peripheral Nervous
System)System) Somatic
◦ Called the voluntary nervous system
◦ Motor neurons are the ones that activate different muscles and glands
◦ Allows for conscious control of your muscles and lets you control your movement
◦ There is also an involuntary component involved in reflexes
Autonomic◦ Called the involuntary
nervous system◦ Sympathetic: called
the fight or flight response (increased heart rate, pupils dilate, etc)
◦ Parasympathetic: resting response (decrease heart rate, pupils constrict, etc)
Sensory OrgansSensory OrgansThere are many different sensory
receptors depending on what they detect◦Mechanoreceptor: responds to
movement, pressure and tension◦Photoreceptor: responds to light◦Chemoreceptor: responds to chemicals◦Thermoreceptor: responds to
temperature change◦Pain receptor: responds to tissue
damage
Hearing and balance Hearing and balance (Diagram on p.1017)(Diagram on p.1017)
The outer ear is responsible for “capturing” sound and transmitting it down the auditory canal
The auditory canal leads to the tympanic membrane or eardrum
Sound vibrations (moving air) cause the tympanic membrane to vibrate and move three small bones: the hammer, the anvil and the stirrup
Hearing and balanceHearing and balanceAfter the three bones are set in motion,
the stirrup transfers vibrations to a membrane called the oval window
The oval window leads into the cochlea◦The cochlea has 3 fluid filled chambers that
are separated by membranes◦Vibrations from the oval window cause hair
cells within the fluid of the cochlea to move◦This movement is interpreted and sent by
your auditory nerve to your brain as sounds
Hearing and balanceHearing and balance In addition to hearing, the ears are responsible
for maintaining balance◦ In the middle ear there is a tube connecting to
the throat, Eustachian tube This allows air pressure to equalize on both
sides of the tympanic membrane (popping your ears)
Additionally, in the inner ear, there are 3 fluid filled chambers called the semicircular canals◦ Each canal is situated in one of 3 axis◦ There are mechanoreceptors in the
semicircular canals that can be interpreted as relative position
Vision: Vision: (Diagram on p. 1019)(Diagram on p. 1019)All sight is based on light striking a place
in the back of the eye called the retina◦Light first passes through the cornea, a
protective outer layer of the eye◦Next, light passes through the pupil, or the
opening in the eye that controls the amount of light It contracts when very bright It dilates when dim or when “fight or flight” is
active
◦The muscles that control the pupil are located in the pigmented iris
VisionVision The light that passes through the iris hits the lens
◦ This is a crystalline structure that allows the light to be refracted, bent, to produce a clear image If your lens cannot be properly “bent”, you will
need some sort of vision correction (glasses, contacts)
Again, the muscles in the iris controls the amount of light passing into the eye
Within the retina are specialized photorecptors called rods and cones◦ Rods respond to dim light◦ Cones respond to bright light
The signals that hit the rods and cones are sent by the optic nerve to be interpreted by the brain
Taste and smellTaste and smellMost people perceive taste
because of chemoreceptors located on the tongue, or taste buds◦Taste buds are located between the
bumps on your tongue, papillae◦You have chemoreceptors for:
sweet, salty, sour and bitter◦The signals are sent to the brain to
interpret taste.
Taste and smellTaste and smellSmell works very similar to tasteInstead of chemoreceptors on
your tongue, smell has specialized chemoreceptors in your nasal passages called olfactory receptors◦When a chemical binds to an
olfactory receptor, the information is sent to your brain and interpreted as smell
TouchTouchYou have many mechanoreceptors throughout
the skin◦They are concentrated in the face, tongue and
fingertipsYou have two types of thermoreceptors in the
skin◦Sensitive below 20°C (cold receptor)◦Sensitive between 30°C and 45°C (heat
receptor)You have many types of “pain” receptors
located throughout the skinAll receptors travel to the spinal chord and up to
the brain
Endocrine systemEndocrine system
Endocrine systemEndocrine systemSystem that produce hormones
to regulate body activities◦Hormones are produced by various endocrine and exocrine glands throughout the body Endocrine glands: ductless gland that
secrete hormones into the blood stream or fluids of nearby tissues
Exocrine glands: gland with a tube-like structure that transport substances to specific locations inside or outside the body
HormonesHormonesHormones are chemicals that influence body
activity. They are transported throughout the body using the blood stream and extracellular fluid◦ Amino-acid based hormone: water soluble
hormone Binds to protein receptors on the cell membrane Often the first to trigger a signal in the cell
◦ Steroid hormone: lipid soluble hormone Lipid soluble allows the hormone to enter
through the plasma membrane Causes the cell to activate existing enzymes or
to initiate protein synthesis for specific enzymes
Organs of the endocrine Organs of the endocrine systemsystemHypothalamus
PituitaryThyroidAdrenalGonads
PancreasThymusPinealParathyroidDigestive cells
Hypothalamus/Pituitary: Hypothalamus/Pituitary: List of hormones released (p. List of hormones released (p.
1035)1035)Hypothalamus: “controls” much of the endocrine system◦Located in the part of the brain that
initiates many of the responses of the endocrine and nervous system
◦The hypothalamus often starts the hormone response by sending signals to the pituitary gland Releasing hormones: stimulates the pituitary
gland to release hormones (ON SWITCH) Release-inhibiting hormones: inhibit the release
or production of hormones (OFF SWITCH)
Thyroid Thyroid Thyroid gland: located near the lower part of the
larynx◦ Thyroid hormones help to maintain normal heart
rate, blood pressure and body temperature◦ Also helps to transport calcium from the blood to
the bone to generate bone tissue for healthy bone development and repair
Hyperthyroidism: produce to much thyroid hormone◦ Symptoms include: hyperactivity, weight loss,
high blood pressure, increased heart rateHypothyroidism: do not produce enough thyroid
hormone◦ Symptoms include: lethargy, lack of growth,
weight gain, low heart rate, low body temp
AdrenalsAdrenalsAdrenal glands: one adrenal is located
above each of the kidneys◦Produces epinephrine and norepinephrine (also known as adrenaline and noradrenaline) Initiates fight or flight respons – increased
heart rate and blood pressure, increase blood sugar levels, increase oxygen flow to lungs
◦Also produces cortisol which promotes the cells to produce glucose from proteins This hormone is often released when the
individual is stressed
GonadsGonadsGonads begin producing hormones when the individual hits puberty◦Responsible for the development of secondary sex characteristics
◦Responsible for the maintaining the production or release of the sex cells
PancreasPancreasThe pancreas is important because of its
production of insulin◦ Insulin is responsible for regulating the levels of
glucose available in the blood and available to cells
◦ Diabetes mellitus is a condition where cells are unable to receive blood glucose so there is a high level of glucose in the blood Type 1: The immune system attacks the cells
that produce insulin (usually treated with a daily insulin injection)
Type II: A hereditary condition that is usually triggered by obesity and inactivity (may be treated with diet and exercise)
Thymus / Pineal / Parathyroid Thymus / Pineal / Parathyroid //
Digestive cellsDigestive cellsThymus: produces that hormones that stimulates the maturation of T-cells
Pineal: releases melatonin which helps to regulate sleep patterns
Parathyroid: causes calcium to be transferred from the bone to the blood (opposite of thyroid and must in unison)
Digestive cells: helps to release various fluids during digestion (stomach acid, digestive enzymes, gastric juices)
Homeostasis: How it Homeostasis: How it worksworksThe ability or tendency of an organism or
cell to maintain internal equilibrium by adjusting its physiological processes
In animals such as ourselves, the internal environment of our bodies must have certain conditions within tolerable limits to continue to function properly
Environmental conditions that cause reactions are called stimuli (plural = stimulus)
A feedback mechanism occurs when the level of one substance influences the level of another substance or activity of another organ.
Negative FeedbackNegative FeedbackNegative feedback is where various
receptors and effectors bring about a reaction to ensure that conditions remain favorableIn negative feedback, a final step in a
reaction inhibits the start of another reaction◦ A receptor is a structure that monitors
internal conditions, sense changes, and initiate a response (usually by sending signals to the brain)
◦ Effectors are muscles, organs, or other structures that receive signals from the brain. When an effector receives a signal from the brain, it changes its function in order to correct the change from normal conditions.
Positive FeedbackPositive FeedbackPositive feedback mechanisms are
designed to accelerate or enhance the output created by a stimulus that has already been activated
Push levels/conditions in the body out of normal ranges
When the body senses a change, it increases or accelerates that change
Happens much less often than negative feedback
HomeostasisHomeostasisDepending on the physiological conditions, a
hormone can act as a positive or a negative feedback◦ For example if you release an initial hormone
and it causes subsequent hormones to be released, this is positive feedback Adrenocorticotropic hormone (ACTH):
stimulates the production of cortisol in the adrenals
◦ When a hormone inhibits the release of a hormone, this is negative feedback Release-inhibiting hormones produces by the
hypothalamus prevents the production of hormones in the pituitary