CHAPTER 5 – 6 HOMEOSTASIS

Section 1: Feedback LoopsSection 2: Circulatory SystemSection 3: Respiratory SystemSection 4: Immune System

SECTION 1: FEEDBACK SYSTEMS

BACKGROUND 1. Organisms use feedback systems to

maintain internal balance and respond to changing conditions.

a. Two Types: Negative Feedback Positive Feedback

TYPES OF FEEDBACK SYSTEMS1. Used to return the body to normal

conditions.2. There is a ‘set point’ for many values

in the bodya. Temperatureb. pH of bloodc. Blood pressured. Water and salt balance

3. When the body moves away from the ‘set point’, something will happen to get it back to normal.

4. Very similar to how a thermostat works in your house

MAINTAINING INTERNAL CONDITIONS5. Examples of Negative feedback loops

a. Carbon dioxide & Breathing rate Increased CO2 makes the blood acidic – body

responds to return to normalb. Exercise

Carbon dioxide levels increase as cells work harder

Respiratory system responds by stimulating diaphragm to contract more rapidly

Breathing rate increases, more CO2 is released from body, blood pH returns to normal

Involuntary regulatory system

SET POINTNormal

blood pH is 7.4 – 7.6

Exercise Requires O2

and Produces CO2

High level of CO2 (low pH)

in blood detected by

brain

Brain sends signal to lungs &

diaphragm

Breathing rate increases

Extra CO2 is removed and

more O2 taken in

MAINTAINING INTERNAL CONDITIONS

c. Hyperventilation Occurs when carbon dioxide is lost more rapidly

than it is produced Caused by:

FeverAspirin poisoningAnxiety

Hyperventilation causes blood pH to become too basic* How does breathing into a paper bag help this condition?

SET POINTNormal

blood pH is 7.4 – 7.6

Hyperventilation - too much CO2 released (pH increases)

Breathe into paper bag

Extra O2 is released and some CO2 is

taken in

CO2 decreases blood pH

POSITIVE FEEDBACK1. Organisms use positive feedback to

complete a critical process quickly in order to get back to normal

a. Keeps moving in a cycle until completed Blood clotting Labor

b. Similar to the “vicious cycle”

BLOOD CLOTTING2. Examples

a. Blood Clotting Clotting proteins (factor proteins) respond to the

scene and pile up to create a clot These proteins signal more factor proteins,

which signal even more There are many different types of factor proteins

for different types of wounds Process continues until clot is made and

bleeding has stopped.

BLEEDING

Clotting proteins (factor) respond

Signal more proteins to

respond

Bleeding Stops

SECTION 2: CIRCULATORY SYSTEM

CIRCULATORY SYSTEM ANATOMY1. Three main parts:

a. Bloodb. Heartc. Blood vessels

CIRCULATORY SYSTEM ANATOMY1. Importance of Blood

a. Red blood cells (Erythrocytes)b. Contains hemoglobin - Carries dissolved

gasses Protein found in red blood cells Oxygen binds to hemoglobin and is transported

to all tissues of the bodyc. White blood cells (Leukocytes)

Defend the body against diseased. Platelets

Involved in blood clottinge. Plasma

Liquid part of the blood Makes up about 55% of the total blood volume

HEART A muscular organ that pumps blood

throughout the body. Pumps about 5L of blood a minute. It beats an average of 100,000 times a

day It pumps about 200,000 gallons of blood

a day. It is about the size of your fist. It has four chambers or “rooms” that

hold blood. Pacemaker

small bundle of cells that controls the rhythm of the heart.

HEART ANATOMY1. The atria (atrium) are chambers that

receive blood returning to the heart.

HEART ANATOMY2. Below the atria are the ventricles

which are thick walled chambers that pump blood away from the heart.

HEART ANATOMY3. Series of valves prevent blood from

going backward

http://www.pbs.org/wgbh/nova/body/map-human-heart.html

HEART ANATOMY4. Heart Beat:

a. Lub sound: Tricuspid and Mitral valve close:

heart contracting, pushing bloodb. Dub sound: Pulmonary and Aortic valves

close: heart fills with blood—pause takes longer

c. Heart murmur—one valve doesn’t close completely

http://depts.washington.edu/physdx/heart/demo.html

Why do we show half of the heart as blue and the other half as red?

BLOOD FLOW1. The Heart pumps the oxygen rich

blood throughout the body in ARTERIES2. Oxygen Poor blood is pumped back to

the heart in VEINS

*There is one exception to thisrule!

BLOOD FLOW

3. The path of blood:a. Heartb. Arteryc. Arteriolesd. Capillariese. Venulesf. Veinsg. Heart

BLOOD FLOW3. Pulmonary Circuit:

Venules↓

Veins (Superior Vena Cava from above the heart and Inferior Vena Cava from below

the heart)↓

Heart (deoxygenated blood)↓

LUNGS

BLOOD FLOW

RBC

Lung cell

Lung cell

Lung cell

Lung cell

AlveoliHigh in O2

Take in CO2

RBCHigh in CO2

Take in O2

O2

CO2

o How do O2 particles move into RBC and CO2 particles into the Alveoli?• diffusion (no energy)

o The blood is now oxygenated and moves back to the heart.

BLOOD FLOW4. Systemic Circuit:

Heart (Oxygenated Blood from lungs)↓

Aorta↓

Arterioles↓

Capillaries

CELLS CLOSE TO BLOOD POOL

What is exchanged at the capillaries? - Oxygen- Carbon

dioxide- Nutrients- Hormones

BLOOD FLOW5. The heart itself cannot get nutrients

and oxygen from its own chambers. Why?

a. It’s too thick for diffusion to work. It must rely on coronary arteries—lie in grooves that spiral around the heart.

HEART DISEASE1. Kills one million

people a year2. Atherosclerosis

a. Heart disease caused by narrowing of the arteries

b. Cholesterol plaques build up inside arteries

c. Causes abnormal blood flow

HEART DISEASEd. An obstruction to any of these coronary

arteries would require bypass surgery to restore proper blood flow

HEART DISEASE3. Blood Pressure -

Pressure exerted by the blood on the walls of blood vessels

HEART DISEASE4. Heart attack

a. Occurs when the arteries that deliver oxygen to the heart become blocked.

b. Usually occurs in the coronary arteriesc. Heart cells begin to die after 4 – 6 hours

without blood

HEART ATTACK Risk Factors

High cholesterolHigh blood

pressureSmokingFamily historyDiabetes

Prevention Early diagnosis of

heart diseaseTreatment of high

blood pressureRegular medical

checkupsHealthy dietRegular exercise

ECG (ELECTROCARDIOGRAM) MACHINES

Measure electrical pulses in the heart.

ELECTROCARDIOGRAM

SECTION 3: THE RESPIRATORY SYSTEM

ANATOMY OF THE RESPIRATORY SYSTEM1. Lungs

a. Made of 5 lobesb. Connects with the

external environment through the trachea (wind pipe)

c. Inhale Oxygen

d. Exhale Carbon dioxide

Without oxygen, your body can not obtain enough energy from food to survive!

Carbon dioxide waste is toxic to cells and must be removed!

ANATOMY OF THE RESPIRATORY SYSTEM2. Nose

a. Air is warmed, moistened, and cleaned

3. Larynxa. Contains vocal

cords 4. Trachea (windpipe)

a. Tube lined with cilia (hair-like structures) that sweep debris out of trachea

ANATOMY OF THE RESPIRATORY SYSTEM5. Bronchioles

Branches leading to each lobe of the lungs

6. Alveoli Smallest lung

compartment Oxygen and carbon

dioxide diffuse across thin walls called alveolar membranes

RESPIRATORY DISEASE Asthma – when bronchioles of the lungs

become constricted because of sensitivity to certain stimuli.

- The constriction makes it difficult for oxygen to

reach the blood.Emphysema – caused by cigarette smoke - lung tissue loses its elasticity and it

becomes more difficult for lungs to expand and take in air

Lung cancer – carcinogens from cigarette smoke cause cancerous tumors to grow on lung tissue.

SECTION 4IMMUNESYSTEM

WHAT IS A VIRUS? Pathogen-causes disease Infect cells and use the cell to make

more viruses

ARE VIRUSES ALIVE? No!

Do not growCan not reproduce without a host cellNot made of cells

NONSPECIFIC DEFENSE Doesn’t have to recognize a specific

invaderSkinMucusSalivaTearsSweatHair

SPECIFIC LINE OF DEFENSEUsing antibodies to target a specific

pathogen.Ex: if you’ve had the chicken pox, you have

antibodies ready to go in case you get infected again.

They PLAN an ATTACK on a TARGET

The BloodMobileCirculatory System

Respiratory System

Immune System

Urinary System

Digestive System

Right ventricle

lungs White blood cells

liver Small intestine

RBC oxygen antibodies kidneysheart Carbon

dioxideWBC

nutrients

WRITING YOUR MATERIALS AND METHODS!

Physiology Lab

Write this in your notes:

Vital Sign to Measure

Tools to Use What to measure Normal Range (Resting)

Write this in your notes:

Vital Sign to Measure

Tools to Use What to measure Normal Range (Resting)

Breathing Rate

Stopwatch # of breaths in 15 sec. (x4) About 12 breaths per minute

Heart Rate

Stopwatch -Find carotid or radial artery-# of beats in 15 sec. (x4)

60 – 100 beats per minute

Blood Pressure

Sphygmoman-ometer (Cuff)

Stethoscope

-Systolic Pressure (first beat, top #) – Maximum pressure in brachial artery-Diastolic Pressure (last beat, bottom #) – Pressure between heart beats when heart is filling with blood

120/80

Materials

StethoscopeSphygmomanometer

Blood pressure cuffStopwatch

Methods

1. Measure your resting breathing rate. a. Count the number of breaths for 15 sec and

multiply by 4.b. Normal BR is about 12 breaths per minute.

Methods

2. Measure your resting heart rate (pulse).a. Find your carotid artery on your neck or your

radial artery on your wrist.b. Count the number of beats for 15 sec and multiply

by 4.c. Normal HR is 60-100 beats per minute.

Methods

3. Measure your resting blood pressure.a. Wrap the cuff around your upper arm.b. Put the stethoscope on inner elbow.c. Pump cuff to 180 mm Hg.d. SLOWLY release the pressure, then listen carefully

for the first beat. (You are listening to the Korotkoff sounds.)

1) This is your systolic pressure (top number).1) The maximum pressure in your brachial artery

Methods

e. Keep listening until you hear the last beat.

1) This is your diastolic pressure (bottom number).

a. The pressure between heart beats – the heart is relaxed and is filling with blood.

f. Normal BP is 120/80.

Methods

4. Record results on table.5. Exercise-run up and down the stairs 5

times, repeat steps 1-3 and record on table.