Circulatory system

made up of 3 parts organ

heart tissues & cells

blood vessels arteries veins capillaries

blood red blood cells plasma

Your Blood: Transport Fluid

Blood is a tissue of fluid & cells

Transports O2 and nutrients to cells

Takes away CO2 and other wastes

Aids in fighting disease Helps maintain body

temp.

Your Blood: Transport Fluid

Blood composition:Plasma: 55% (liquid part)Blood cells: 45% (red, white,

& platelets

Blood Cell production ribs, vertebrae, breastbone & pelvis

Stem cells “parent” cells in

bone marrow differentiate into

many different types of cells

white bloodcells

red bloodcells

white blood cells

Red blood cells: Oxygen carriers

Bioconcave disc shaped, most numerous

No nucleus when mature; ‘live’ ≈120 days

5-6 million RBC in one drop of human blood

Produced in red marrow of long bones

contain hemoglobin that enables transport of O2

Hemoglobin Protein which binds O2

250,000 hemoglobin in 1 red blood cell

O2

O2O2

O2

White blood cells: Infection fighters

Largest blood cell play a major role in

protecting your body from foreign substances.

White Blood Cells

Platelets: Blood clotting

Smallest (fragments) help form blood clot

after an injury.

Short-lived

Blood vesselsarteries

arterioles

capillaries

venules

veins

artery

arteriolesvenules

veins

Arteries: Built for pressure Arteries

blood flows away from heart thicker walls

provide strength for high pressure pumping of blood

elastic & resistant maintains blood

pressure even when heart relaxes

Major arteries

pulmonaryartery

pulmonaryartery =to lungs

aorta carotid = to headto brain & left arm to right arm

coronary arteries

to body

Veins: Built for flexibility Veins

blood returns back to heart thinner-walled blood travels back to heart

at low speed & pressure far from heart

blood flows because muscles contract when we move squeeze blood through veins

one-way valves in larger veins allow blood to flow only towards heart

Open valve

Blood flowstoward heart

Closed valve

Major Veins

pulmonaryvein =

from lung

superiorvena cava = from upper body

pulmonaryvein = from lung

inferiorvena cava = from lower body

Structure-function relationship Capillaries

very thin walls; one cell layer thick

allows diffusion of materials across capillary wall O2, CO2, H2O,

food, waste

body cell

O2

food

waste

CO2

Your Heart: The Vital Pump

Atria: upper chamber which receive blood that pump blood to ventricles

Ventricles: muscular walled chambers which pump blood from heart

leftatrium

rightatrium

leftventricleright

ventricle

2 part system1. Circulation to lungs blood gets O2 from lungs

drops off CO2 to lungs

brings O2-rich blood from lungs to heart

2. Circulation to body pumps O2-rich blood to body picks up nutrients from

digestive system collects CO2 & cell wastes

Circulation of Blood

heart

lungs

body

Circulationto lungs

Circulationto body

Blood’s path through the heart

1. vena cava 2. right atrium 3. valve 4. right ventricle 5. valve 6. pulmonary artery

(to lungs)

Blood’s path through the heart

7. pulmonary veins 8. left atrium 9. valve 10. left ventricle 11. valve 12. aorta: largest

blood vessel in the body

Heartbeat regulation

The surge of blood through an artery is called a pulse.

Pacemaker: initiates heartbeat & generates an electrical impulse that spreads over both atria.

Sino atrial node (Pacemaker node)

Blood pressure

the force that the blood exerts on the blood vessels

Blood pressure is measured as systolic (ventricles contract) and diastolic (ventricles relax) pressures

Control of the heart

A portion of the brain called the medulla oblongata regulates the rate of the pacemaker, speeding or slowing its nerve impulses.

Medulla oblongata

Control of the heart

If the heart beats too fast, the medulla oblongata sends signals that slow the pacemaker.

If the heart beat slows down the medulla oblongata sends signals to speed up the pacemaker and increase the heart rate.

Medulla oblongata

waste

food

Circulatory System & Homeostasis

Homeostasis keeping the internal

environment of the body balanced

need to balance food & O2 in need to balance energy (ATP)

production need to balance CO2 & waste

out

O2

ATP

CO2

waste

food

Circulatory System & Homeostasis

Exercise heart beat faster need more ATP bring in more O2 & food; remove

more CO2 & waste out Disease

poor lung or heart function = heart beat faster

need to work harder to bring in O2 & food & remove wastes

O2

ATP

CO2

Cardiovascular disease

Atherosclerosis & Arteriosclerosis deposits inside arteries (plaques)

develop in inner wall of the arteries, narrowing their channel

normal artery hardening of arteries

Cardiovascular disease

Atherosclerosis & Arteriosclerosis increase blood pressure increase risk of heart attack, stroke, kidney

damage

normal artery hardening of arteries

Cardiovascular healthbypass surgery Risk Factors

genetics diet

high animal fat exercise & lifestyle

smoking lack of exercise

Women & Heart Disease

Heart disease is 3rd leading cause of death among women aged 25–44 years & 2nd leading cause of death among women aged 45–64 years.

Risk factorsSmokingLack of exerciseHigh fat dietOverweight

Death rates for heart disease per 100,000 women, 2002

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