chapter 1 the human body: an orientation
DESCRIPTION
Chapter 1 The Human Body: An Orientation. Define anatomy and physiology . Anatomy Study of the structure and shape of the body and its parts Physiology Study of how the body and its parts work or function. Explain how anatomy and physiology are related. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 1The Human Body: An Orientation
Define anatomy and physiology.
Anatomy– Study of the structure and shape of the body and
its partsPhysiology
– Study of how the body and its parts work or function
Explain how anatomy and physiology are related
• Anatomy has to do with the names and relationships of the structures of the body and physiology is how those structures work.
Which of the following is an example of applied physiology: a. measuring the length of the femur on a fetus using ultrasound b. locating an injury to a tendon in the shoulder using CT imaging c. describing the process of how a toxin interferes with nerve impulse conduction d. identifying the types of cells found in a biopsy sample of lung
tissue
Name the levels of structural organization that make up the human body and explain how they are related.
1. Chemical : Atoms & Molecules
2. Cellular : Cells are made up of molecules
3. Tissue: Tissues consist of similar types of cells
4. Organ: Organs are made up of different typesof tissues
5. Organ System: Organ systems consist of differentorgans that work together closely
6. Organism: Human organisms are made up of manyorgan systems
Levels of Structural OrganizationMolecules
Atoms
Smoothmuscletissue
EpithelialtissueSmooth
muscletissueConnective
tissue
Bloodvessel(organ)
Cardio-vascularsystem
Cellular levelCells are made up of molecules
Tissue levelTissues consist ofsimilar types of cells
Organ levelOrgans are made upof different typesof tissues
Organ system levelOrgan systems consist of differentorgans that work together closely
Organismal levelHuman organismsare made up of manyorgan systems
Chemical levelAtoms combine toform molecules
Name the organ systems of the body and briefly state the major functions of each system.Classify by organ system all organs discussed.
1. Integumentary 7. Lymphatic2. Skeletal 8. Respiratory3. Muscular 9. Digestive4. Nervous 10. Urinary5. Endocrine 11. Reproductive6. Cardiovascular
Figure 1.2a
Integumentary
Functions– Forms the external body
covering– Protects deeper tissue from
injury– Helps regulate body
temperature– Location of cutaneous
nerve receptors
Figure 1.2b
Skeletal
• Functions– Protects and supports
body organs– Provides muscle
attachment for movement– Site of blood cell
formation– Stores minerals
Figure 1.2c
Muscular
• Functions– Produces movement– Maintains posture– Produces heat
Nervous
• Function– Fast-acting control
system– Responds to internal and
external change– Activates muscles and
glands
Figure 1.2d
Endocrine
• Function– Secretes regulatory
hormones• Growth• Reproduction• Metabolism
Figure 1.2e
Figure 1.2f
Cardiovascular
• Function– Transports materials in body
via blood pumped by heart• Oxygen• Carbon dioxide• Nutrients• Wastes
Lymphatic• Function
– Returns fluids to blood vessels
– Cleanses the blood– Involved in immunity
Figure 1.2g
Respiratory• Function
– Keeps blood supplied with oxygen
– Removes carbon dioxide
Figure 1.2h
Digestive• Function
– Breaks down food– Allows for nutrient
absorption into blood– Eliminates indigestible
material
Figure 1.2i
Urinary• Function
– Eliminates nitrogenous wastes
– Maintains acid-base balance
– Regulates water and electrolytes
Figure 1.2j
Reproductive• Function– Produces
offspring
Figure 1.2k–l
Verbally describe or demonstrate the anatomical position.
• The position with the body erect with the arms at the sides and the palms forward.
Use proper anatomical terminology to describe body directions, surfaces, and body planes.
• Superior/Inferior• Ventral/dorsal• Medial/Lateral• Proximal/ Distal
SEE BELOW FOR DETAILS
Figure .5a
Use proper anatomical terminology to describe body directions, surfaces, and body planes.
Use proper anatomical terminology to describe body directions, surfaces, and body planes.
• A sagittal section divides the body (or organ) into left and right parts
• A median, or midsagittal, section divides the body (or organ) into equal left and right parts
• A frontal section divides the body (or organ) into anterior and posterior parts
• A transverse, or cross, section divides the body (or organ) into superior and inferior parts
SEE BELOW FOR DIAGRAMS
Use proper anatomical terminology to describe body directions, surfaces, and body planes.
Body Directions
Body Directions
Use proper anatomical terminology to describe body directions, surfaces, and body planes.
Locate the major body cavities and list the chief organs in each cavity.
• Dorsal body cavity– Cranial cavity houses the brain– Spinal cavity houses the spinal cord
• Ventral body cavity– Thoracic cavity houses heart, lungs and others– Abdominopelvic cavity houses digestive system
and most urinary system organs
Locate the major body cavities and list the chief organs in each cavity.
Chapter 3: Cells and Tissues
Define cell• 1. The structural, functional and biological unit of all
organisms. • 2. An autonomous self-replicating unit that may exist as
functional independent unit of life (as in the case of unicellular organism), or as sub-unit in a multicellular organism (such as in plants and animals) that is specialized into carrying out particular functions towards the cause of the organism as a whole.
• 3. A membrane bound structure containing biomolecules, such as nucleic acids, proteins, and polysaccharides
Define organelle.
• Literally, the term means "little organs". As the body is composed of various organs, the cell, too, has "little organs" that perform special functions. They are membrane-bound compartments or structures of a cell.
Define inclusion.
• are non-living substances that may or may not be present in a cell, depending on the cell type. Inclusions are stored nutrients, secretory products, and pigment granules.
• Examples of inclusions are glycogen granules in the liver and muscle cells, lipid droplets in fat cells, pigment granules in certain cells of skin and hair, water containing vacuoles, and crystals of various types.
Identify on a cell model or diagram the three major cell
regions (nucleus, cytoplasm, and plasma membrane).
List the structures of the nucleus and explain the function of chromatin and nucleoli.
– Nuclear envelope (membrane)
– Nucleolus: Sites of ribosome assembly
– Chromatin: Composed of DNA and protein, Present when the cell is not dividing, Scattered throughout the nucleus, Condenses to form chromosomes when the cell divides
Identify the organelles on a cell model or describe them, and discuss the major function of each.
Mitochondria
– “Powerhouses” of the cell– Change shape continuously– Carry out reactions where oxygen is used to break
down food– Provides ATP for cellular energy
Ribosomes
– Made of protein and RNA– Sites of protein synthesis– Found at two locations
• Free in the cytoplasm• As part of the rough endoplasmic reticulum
Endoplasmic reticulum (ER)
– Fluid-filled tubules for carrying substances– Two types of ER
• Rough endoplasmic reticulum– Studded with ribosomes– Synthesizes proteins
• Smooth endoplasmic reticulum– Functions in lipid metabolism and detoxification of drugs and
pesticides
Golgi apparatus
– Modifies and packages proteins– Produces different types of packages
• Secretory vesicles• Cell membrane components• Lysosomes
Lysosomes
• Lysosomes– Contain enzymes that digest worn-out or
nonusable materials within the cell
Cytoplasmic Organelles
• Peroxisomes– Membranous sacs of oxidase enzymes
• Detoxify harmful substances such as alcohol and formaldehyde
• Break down free radicals (highly reactive chemicals)– Replicate by pinching in half
Peroxisomes
– Membranous sacs of oxidase enzymes• Detoxify harmful substances such as alcohol and
formaldehyde• Break down free radicals (highly reactive chemicals)
– Replicate by pinching in half
Cytoskeleton
– Network of protein structures that extend throughout the cytoplasm
– Provides the cell with an internal framework
Figure 3.7a
Centrioles
– Rod-shaped bodies made of microtubules– Direct the formation of mitotic spindle during cell
division
Define selective permeability,
selective permeability• The plasma membrane allows some materials
to pass while excluding others• This permeability influences movement both
into and out of the cell
Define diffusion
Diffusion– Particles tend to distribute themselves evenly
within a solution– Movement is from high concentration to low
concentration, or down a concentration gradient
• Define Simple diffusion• An unassisted process; Solutes are lipid-soluble materials or
small enough to pass through membrane pores• Define Osmosis—
• simple diffusion of water; Highly polar water molecules easily cross the plasma membrane through aquaporins
Define facilitated diffusion• Substances require a protein carrier for passive transport• Transports lipid-insoluble and large substances
Describe plasma membrane structure and explain how the various transport processes account for the directional movements of specific substances across the plasma membrane.
Explain how the various transport processes account for the directional movements of specific substances across the plasma membrane.
1. Passive Transport: See diffusion above2. Active Transport:
1. Solute Pumping2. Exocytosis3. EndocytosisSEE DETAILS BELOW
Solute Pumping
– Amino acids, some sugars, and ions are transported by protein carriers called solute pumps; ATP energizes protein carriers; In most cases, substances are moved against concentration gradients
Exocytosis
• Moves materials out of the cell• Material is carried in a membranous vesicle• Vesicle migrates to plasma membrane• Vesicle combines with plasma membrane• Material is emptied to the outside
Endocytosis
• Extracellular substances are engulfed by being enclosed in a membranous vescicle
Types of endocytosis• Phagocytosis—“cell eating”• Pinocytosis—“cell drinking
Name some cell types, and relate their overall shape and internal structure to their special functions.
Name the four major tissue types and their chief subcategories. Explain how the four major tissue types differ structurally and functionally.
1. (epithelium)• Functions
Tissue Function Structure
Epithelial tissue • Protection• Absorption• Filtration• Secretion
• Cells fit closely together and often form sheets
• The apical surface is the free surface of the tissue
• The lower surface of the epithelium rests on a basement membrane
• Avascular (no blood supply)• Regenerate easily if well nourished
Connective tissue • Binds body tissues together; • Supports the body; • Provides protection
Variations in blood supply- • Some tissue types are well vascularized • Some have a poor blood supply or are
avascularExtracellular matrixNon-living material that surrounds living cells
Muscle tissue to produce movement Skeletal muscleCardiac muscleSmooth muscle
Nervous tissue Function is to send impulses to other areas of the body (Irritability & Conductivity)
Composed of neurons and nerve support cells
Simple Epithelia
• Simple squamous Single layer of flat cells• Usually forms membranes• Lines body cavities• Lines lungs and capillaries
• Simple cuboidal Single layer of cube-like cells• Common in glands and their ducts• Forms walls of kidney tubules• Covers the ovaries
• Simple columnar Single layer of tall cells• Often includes mucus-producing goblet cells• Lines digestive tract
• Pseudostratified columnar Single layer, but some cells are shorter than othersOften looks like a double layer of cells• Sometimes ciliated, such as in the respiratory tract• May function in absorption or secretion
Stratified Epithelia
• Stratified squamous Cells at the apical surface are flattened• Found as a protective covering where friction is common• Locations: Skin, Mouth, Esophagus
• Stratified cuboidal—two layers of cuboidal cells• Stratified columnar—surface cells are columnar, cells underneath
vary in size and shape– Stratified cuboidal and columnar– Rare in human body– Found mainly in ducts of large glands
• Transitional epithelium– Shape of cells depends upon the amount of stretching– Lines organs of the urinary system
Glandular Epithelium
• Gland: One or more cells responsible for secreting a particular product
• Two major gland types– Endocrine gland
– Ductless since secretions diffuse into blood vessels– All secretions are hormones
– Exocrine gland– Secretions empty through ducts to the epithelial surface– Include sweat and oil glands
Connective Tissue Types1. Bone (osseous tissue)2. Hyaline cartilage3. Elastic cartilage4. Fibrocartilage5. Dense connective tissue (dense fibrous tissue)
• Tendons—attach skeletal muscle to bone• Ligaments—attach bone to bone at joints• Dermis—lower layers of the skin
6. Loose connective tissue types• Areolar tissue• Adipose tissue• Reticular connective tissue
7. Blood (vascular tissue)
Types of Muscle TissueSkeletal muscle Cardiac muscle Smooth muscle• Under voluntary control• Contracts to pull on bones or
skin• Produces gross body
movements or facial expressions
• Characteristics of skeletal muscle cells
o Striatedo Multinucleateo Long, cylindrical
• Under involuntary control• Found only in the heart• Function is to pump
blood• Characteristics of cardiac
muscle cells Cells are attached to other cardiac
muscle cells at intercalated disks Striated One nucleus per cell
• Under involuntary muscle• Found in walls of hollow
organs such as stomach, uterus, and blood vessels
• Characteristics of smooth muscle cells
o No visible striationso One nucleus per cello Spindle-shaped cells
Chapter 4: Skin
List several important functions of the integumentary system and explain how these functions are accomplished.
On diagram of the skin, recognize and name the following skin structures: epidermis, dermis (papillary and reticular layers), hair and hair follicle, sebaceous gland, and sweat gland.
Describe the distribution and function of the epidermal derivatives-sebaceous glands, sweat glands, and hair.
Sebaceous glands Sweat glands Hair
• Produce oil• Lubricant for skin• Prevents brittle hair• Kills bacteria• Glands are activated at
puberty
Produce sweat 1. Eccrine: Open via duct to pore on skin surface2. Apocrine: Ducts empty into hair follicles
Composition:• Mostly water• Salts and vitamin C• Some metabolic waste• Fatty acids and proteins
(apocrine only)
Function:• Helps dissipate excess heat• Excretes waste products• Acidic nature inhibits bacteria
growth
Produced by hair follicle
Consists of hard keratinized epithelial cells
Melanocytes provide pigment for hair color
Hair follicle: Dermal and epidermal sheath surround hair rootArrector pili muscle: Smooth muscle; Pulls hairs upright when cold or frightened
Most have ducts that empty into hair follicles; others open directly onto skin surface
Widely distributed in skin
Name the factors that determine skin color and describe the function of melanin.The differences in skin color result from differences in the amount of melanin that melanocytes produce and in the size of the pigment granules.
Melanin• Pigment (melanin) produced by melanocytes• Melanocytes are mostly in the stratum basale• Color is yellow to brown to black• Amount of melanin produced depends upon genetics and exposure to
sunlight
The three pigments that affect skin color are:
1. Melanin 2. Hemoglobin 3. Carotene
Identify the subdivisions of the skeleton as axial or appendicular
Axial Skeleton - forms the longitudinal axis of the body,
skull thoracic cagevertebral column
Appendicular Skeleton bones of the limbs pectoral and pelvic girdles
List at least three functions of the skeletal system.
1. Support the body2. Protect soft organs3. Allow movement due to attached skeletal
muscles4. Store minerals and fats5. Blood cell formation
Name the four main kinds of bones.
Identify the major anatomical areas of a long bone.
DiaphysisShaftComposed of compact bone
Epiphysis Ends of the boneComposed mostly of spongy bone
PeriosteumOutside covering of the diaphysisFibrous connective tissue membrane
Sharpey’s fibersSecure periosteum to underlying bone
Arteries Supply bone cells with nutrientsArticular cartilage
Covers the external surface of the epiphysesMade of hyaline cartilageDecreases friction at joint surfaces
Epiphyseal plateFlat plate of hyaline cartilage seen in young, growing bone
Epiphyseal lineRemnant of the epiphyseal plateSeen in adult bones
Medullary cavity Cavity inside of the shaftContains yellow marrow (mostly fat) in adultsContains red marrow (for blood cell formation) in infants
Explain the role of bone salts and the organic matrix in making bone both hard and flexible
• Bone is a composite material and the brittle in a matrix of a more flexible substance.
• The calcium salts make it strong and hard, the connective tissue makes it tough.
On a skull or diagram, identify and name the bones of the skull
Describe how the skull of a newborn infant (or fetus) differs from that of an adult, and explain the function of fontanels.
• The fetal skull is large compared to the infant’s total body length
• Fontanels—fibrous membranes connecting the cranial bones
• Allow the brain to grow• Convert to bone within 24 months after birth
Name the parts of a typical vertebra and explain in general how the cervical, thoracic, and lumbar vertebrae differ from one another.
Explain in general how the cervical, thoracic, and lumbar vertebrae differ from one another.
Discuss the importance of the intervertebral discs and Discuss the importance of the intervertebral discs and spinal curvatures• The spine has a normal
curvature– Primary curvatures are the
spinal curvatures of the thoracic and sacral regions
• Present from birth– Secondary curvatures are
the spinal curvatures of the cervical and lumbar regions
• Develop after birth
Discuss the importance of the intervertebral discs and spinal curvatures
• The intervertebral discs are fibrocartilaginous cushions serving as the spine's shock absorbing system, which protect the vertebrae, brain, and nerves.
• The discs allow some vertebral motion: extension and flexion
Identify on a skeleton the bones of the shoulder and pelvic girdles and their attached limbs
Identify on a skeleton the bones of the shoulder and pelvic girdles and their attached limbs
• The Pectoral (Shoulder) GirdleClavicle—collarbone & Scapula—shoulder blade
• Bones of the Upper Limbs• Humerus• Ulna• Radius • Carpals—wrist • Metacarpals—palm• Phalanges—fingers
• Bones of the Pelvic Girdle• Formed by two coxal (ossa coxae) bones• Composed of three pairs of fused bones
– Ilium Ischium Pubis
• Bones of the Lower Limbs• Femur • Tibia• Fibula• Tarsals (include Calcaneus (heelbone) & Talus)
• Metatarsals—sole• Phalanges—toes
Describe important differences between a male and female pelvis.• The female inlet is larger and more circular
• The female pelvis as a whole is shallower, and the bones are lighter and thinner
• The female ilia flare more laterally
• The female sacrum is shorter and less curved
• The female ischial spines are shorter and farther apart; thus the outlet is larger
• The female pubic arch is more rounded because the angle of the pubic arch is greater
Male pelvis Female pelvis
Name the three major categories of joints and compare the amount of movement allowed by each
Synarthroses Amphiarthroses Diarthroses
Immovable joints Slightly moveable joints Freely moveable joints
Fibrous joints Cartilaginous joints Synovial joints
Generally immovable joints
Immovable or slightly moveable
Freely moveable joints
Chapter 6: The Muscular System
Describe similarities and differences in the structure and function of the three types of muscle tissue and indicate where they are found in the body.
Define muscular system.
• The bodily system that is composed of skeletal, smooth, and cardiac muscle tissue and functions in movement of the body or of materials through the body, maintenance of posture, and heat production.
Define and explain the role of the following: endomysium, perimysium, epimysium,
– Endomysium—encloses a single muscle fiber
– Perimysium—wraps around a fascicle (bundle) of muscle fibers
– Epimysium—covers the entire skeletal muscle
Define and explain the role of the following: tendon, and aponeurosis.
• Epimysium blends into a connective tissue attachment– Tendons—cord-like structures
• Mostly collagen fibers• Often cross a joint due to toughness and small size
– Aponeuroses—sheet-like structures• Attach muscles indirectly to bones, cartilages, or
connective tissue coverings
Describe the microscopic structure of skeletal muscle and explain the role of actin- and myosin-containing myofilaments.
Thick & Thin Filaments• Thick filaments = myosin filaments
– Composed of the protein myosin– Myosin filaments have heads (extensions, or cross bridges)
• Thin filaments = actin filaments– Composed of the protein actin– Anchored to the Z disc
Describe how an action potential is initiated in a muscle cell.
• Skeletal muscles must be stimulated by a motor neuron (nerve cell) to contract
• Neuromuscular junction• Synaptic cleft :Gap between nerve and muscle• Nerve and muscle do not make contact• Area between nerve and muscle is filled with interstitial fluid• Neurotransmitter—chemical released by nerve upon arrival of nerve impulse (The neurotransmitter for skeletal muscle is acetylcholine (ACh))
• Transmission of Nerve Impulse to Muscle• Acetylcholine attaches to receptors on the sarcolemma• Sarcolemma becomes permeable to sodium (Na+)• Sodium rushes into the cell generating an action potential• Once started, muscle contraction cannot be stopped
Describe the events of muscle cell contraction.
The Sliding Filament Theory of Muscle Contraction• Activation by nerve causes myosin heads (cross bridges) to
attach to binding sites on the thin filament
• Myosin heads then bind to the next site of the thin filament and pull them toward the center of the sarcomere
• This continued action causes a sliding of the myosin along the actin
• The result is that the muscle is shortened (contracted)
Chapter 7The Nervous System
Define central nervous system and peripheral nervous system and list the major parts of each.
• Central nervous system (CNS)– Brain– Spinal cord
• Peripheral nervous system (PNS)– Nerves outside the brain and spinal cord
• Spinal nerves- 31 pairs• Cranial nerves- 12 pairs
State the function of neurons and neuroglia.
• Neurons : transmit messages (nerve impulses) from one part of the body to another.
• Neuroglia– supporting cells act as phaogcytes – protect and myelinate – act as a selective barrier between the capillary
blood supply and neurons
Describe the general structure of a neuron, and name its important anatomical regions.
– Major regions of neurons• Cell body —nucleus and metabolic center of the cell
– Processes —fibers that extend from the cell body
List the two major functional properties of neurons.
• Irritability– Ability to respond to stimuli
• Conductivity– Ability to transmit an impulse
Classify neurons according to structure and function.• Function
• Sensory (afferent) neurons– Carry impulses from the sensory receptors to the CNS
• Motor (efferent) neurons– Carry impulses from the central nervous system to viscera, muscles, or glands
• Interneurons (association neurons)– Found in neural pathways in the central nervous system– Connect sensory and motor neurons
• Structure1. Multipolar neuron have several processes extending from its cell bodyAll motor neurons and interneurons!2. Bipolar neurons—one axon and one dendriteFound in eyes and nose as receptor cells3. Unipolar neurons—have a short single process leaving the cell bodySensory neurons found in PNS ganglia
Describe the events that lead to the generation of a nerve impulse and its conduction from one neuron to another.
• Resting neuron– The plasma membrane at rest is polarized– Fewer positive ions are inside the cell than outside the cell
• Depolarization – A stimulus depolarizes the neuron’s membrane– A depolarized membrane allows sodium (Na+) to flow inside the membrane– The exchange of ions initiates an action potential in the neuron
• Action potential– If the action potential (nerve impulse) starts, it is propagated over the entire axon– Impulses travel faster when fibers have a myelin sheath
• Repolarization– Potassium ions rush out of the neuron after sodium ions rush in, which repolarizes the membrane– The sodium-potassium pump, using ATP, restores the original configuration.
Define reflex and list its elements.
Reflex—rapid, predictable, and involuntary response to a stimulus Reflex arc —direct route from a sensory neuron, to an interneuron, to an effector
Identify and indicate the functions of the major regions of the cerebral hemispheres, diencephalon, brain stem, and cerebellum on a human brain model or diagram.
Cerebral hemispheres (cerebrum)• Frontal lobe• Parietal lobe• Occipital lobe• Temporal lobe
Primary somatic sensory area -Receives impulses from the body’s sensory receptorsPrimary motor area -Sends impulses to skeletal musclesBroca’s area -Involved in our ability to speakGustatory area (taste), Visual area, Auditory areaOlfactory areaSpeech/language regionLanguage comprehension regionGeneral interpretation area
Diencephalon• Thalamus• Hypothalamus• Epithalamus
The relay station for sensory impulsesTransfers impulses to the correct part of the cortex for localization and interpretation
Important autonomic nervous system centerHelps regulate body temperatureControls water balanceRegulates metabolismAn important part of the limbic system (emotions)The pituitary gland is attached to the hypothalamus
Houses the pineal body (an endocrine gland)Includes the choroid plexus—forms cerebrospinal fluid
Functions of major regions of the brain.
Cerebellum Provides involuntary coordination of body movements
Brain stem:• Midbrain• Pons• Medulla oblongata
Midbrain-Reflex centers for vision and hearing
Pons -Includes nuclei involved in the control of breathing
Medulla Oblongata -Heart rate control, Blood pressure regulation, Breathing, Swallowing, Vomiting
Name the three meningeal layers and state their functions.
• Protection of the Central Nervous System
1. Dura mater-outermost layer; tough fibrous connective tissue,
2. Arachnoid layer 3. Pia mater-innermost vascular layer covering
the brain; follows every convolution
Discuss the formation and function of cerebrospinal fluid and the blood-brain barrier.
• Protection of the Central Nervous Systemcerebrospinal fluid
– choroid plexus- structure that forms the cerebrospinal fluid
– Forms a watery cushion to protect the brain
blood-brain barrier– Includes the least permeable capillaries of the body– Excludes many potentially harmful substances
List two important functions of the spinal cord.
1. Conduction pathway2. Reflex center
Describe spinal cord structure.
Extends from the foramen magnum of the skull to the first or second lumbar vertebra31 pairs of spinal nerves arise from the spinal cordCauda equina is a collection of spinal nerves at the inferior end
Describe spinal cord structure.• Internal gray matter is mostly cell bodies
– Dorsal (posterior) horns– Anterior (ventral) horns
• Gray matter surrounds the central canal• Central canal is filled with cerebrospinal fluid• Exterior white mater—conduction tracts
Dorsal, lateral, ventral columns• Meninges cover the spinal cord• Spinal nerves leave at the level of each
vertebrae• Dorsal root- Associated with the dorsal root
ganglia—collections of cell bodies outside the central nervous system
• Ventral root- Contains axons
Describe the general structure of a nerve.
Nerve = bundle of neuron fibers
Neuron fibers are bundled by connective tissue
Endoneurium surrounds each fiberGroups of fibers are bound into fascicles by perineuriumFascicles are bound together by epineurium
Identify the cranial nerves by number and by name, and list the major functions of each.
• I Olfactory nerve—sensory for smell• II Optic nerve—sensory for vision• III Oculomotor nerve—motor fibers to eye muscles• IV Trochlear—motor fiber to eye muscles• V Trigeminal nerve—sensory for the face; motor fibers to chewing muscles• VI Abducens nerve—motor fibers to eye muscles• VII Facial nerve—sensory for taste; motor fibers to the face• VIII Vestibulocochlear nerve—sensory for balance and hearing• IX Glossopharyngeal nerve—sensory for taste; motor fibers to the pharynx• X Vagus nerves—sensory and motor fibers for pharynx, larynx, and viscera• XI Accessory nerve—motor fibers to neck and upper back• XII Hypoglossal nerve—motor fibers to tongue
Describe the origin and fiber composition of (a) ventral and dorsal roots, (b) the spinal nerve proper (c) ventral rami and dorsal rami• There is a pair of spinal nerves at the level of each vertebrae
for a total of 31 pairs• Formed by the combination of the ventral and dorsal roots of
the spinal cord• Named for the region from which they arise
Describe the origin and fiber composition of (a) ventral and dorsal roots, (b) the spinal nerve proper (c) ventral rami and dorsal rami• Spinal nerves divide soon after leaving the
spinal cord• Dorsal rami—serve the skin and muscles of
the posterior trunk• Ventral rami—form a complex of networks
(plexus) for the anterior
Name the four major nerve plexuses, give the major nerves of each, and describe their distribution.
Plexus Major Nerves Area Served
Cervical phrenic nerve serves the diaphragm and muscles of shoulder and neck
Brachial: Axillary Radial Median Musculocutaneous Ulnar
upper limbs
Lumbar FemoralObturator
serve the abdominal region and the anteromedial thigh.
Sacral Sciatic nerve – largest nerve in the body; divides into common fibular nerve and tibial nerve.
Superior and Inferior Glutea
supply buttock, posterior thigh, and almost all leg and foot.
Identify the site of origin and explain the function of the sympathetic and parasympathetic divisions of the autonomic nervous system.• Sympathetic Division = Fight/Flight
Originates from T1 through L2
– Response to unusual stimulus– Takes over to increase activities– Remember as the “E” division – Exercise, excitement, emergency, and embarrassment
• Parasympathetic division = Take it EasyOriginates from the brain stem and S1 through S4
– Conserves energy– Maintains daily necessary body functions– Remember as the “D” division– digestion, defecation, and diuresis
Contrast the effect of the parasympathetic and sympathetic divisions on the following organs: heart, lungs, digestive system, blood vessels
Organ Parasympathetic Sympathetic Heart Decrease heart rate Increase heart rate Lungs Contracts bronchiole (small air
passage) smooth muscle. Dilates bronchioles.
Digestive System Increases peristalsis and enzyme/mucus secretion.
Decreases glandular and muscular activity.
Blood vessels constricts dilates