The Circulatory System

Function:

• Transports nutrients & wastes

• Contains cells that fight infections

• Helps maintain body temperature by

transporting heat

The Circulatory System

All organisms must be able to transport

nutrients and wastes. Smaller organisms

rely on _________ for this movement; humans

require an organized circulatory system for the

movement of substances

through the body. We have a _______

circulatory system, which means our blood is

______________________. The human circulatory

system includes the heart, the blood vessels, and

the blood.

diffusion

closed

contained in vessels

I. THE HEART (pp. 943-946)

ADD TO NOTES

The heart itself is mostly composed of

________ muscle which forms a thick

layer of tissue known as the ____________.

Humans have a __ chambered heart,

divided by a __________ into right and left

sides to prevent _____________

cardiac

myocardium

4septum

Mixing of blood

A. Structure ADD TO NOTES

1. Chambers

a. Atria (atrium = singular) _______

chambers of the heart that ________

blood.

b. Ventricles - _______ chambers of the

heart that ________ blood.

2. Valves – Flaps of tissue that keep blood

flowing _________________

Upper

receive

lower

pump

in one direction

B. Pathway of Blood Through

the Heart

________→_________→___________→

____________→____→____________→

________→_________→____→_______

ADD TO NOTES

vena cava right atrium right ventricle

pulmonary artery lung pulmonary vein

left atrium left ventricle aorta body

C. Circulatory Pathways

1. Pulmonary Circulation – The blood

entering the right atrium from the body is

____ in oxygen and _____ in carbon

dioxide. The flow of blood from the right

side of the heart to the _____ and back

to the heart is referred to as ___________

circulation.

highlow

lungs

pulmonary

C. Circulatory Pathways

2. Systemic Circulation – The blood

entering the left atrium from the

lungs is _____ in O2 and _____ in CO2. The

flow of blood from the left side of the

heart to the ______ and back to the heart

is referred to as __________ circulation.

high low

body

systemic

D. The Heartbeat

1. Stimulus for Contraction

Although the brain can change the rate &

force of contraction, the heart generates

and maintains its own beat. There is a

small cluster of cardiac muscle cells in the

______________ referred to as the __________.

They trigger an ___________ impulse that

stimulates the contraction of cardiac

muscle cells.

right atrium pacemaker

electrical

Sinoatrial

(SA) node

Atrioventricular

(AV) node

Conducting

fibers

Contraction of Atria Contraction of Ventricles

The Sinoatrial Node

D. The Heartbeat

2. The Pulse

The powerful contraction of the _________

causes a surge of blood to leave through the

_____. This surging action of the blood

continues into the ______ that branch off

from the aorta. Each contraction of the left

ventricle results in another surge of blood in the

arteries leading away from the heart. This surge

can be felt and is known as the _____.

left ventricle

aorta

arteries

pulse

Blood Vessels & Blood

Blood Vessels

Arteries

• carry blood _____from heart

• carry oxygen ____blood

(except for__________)

• Have thick elastic walls

surrounded by _____muscle

• ____is the largest artery in

the body

away

rich

pulmonary

smooth

Aorta

Blood Vessels

Capillaries

– ________ blood vessels

– Walls are only 1 cell thick

– This is where the exchange of ______ &

_____ takes place

smallest

nutrients

waste

Blood VesselsVeins

– Collect blood and carry it _____ to the heart

– Carry oxygen _______ blood (except for _____________ veins)

– Have thinner and less elastic walls

– Have _______to keep blood flowing to heart and not _________

– Contraction of _________ muscles help to move blood toward the heart

– The ____________is the largest vein in the body

back

poor

pulmonary

valves

backwards

skeletal

vena cava

Artery vs. Vein

Vein Valves

Blood Pressure: the force of blood

on the walls of the arteries

– Falls when the heart ______

– Heart is always under pressure

in order to keep blood flowing

through it

– Regulated by autonomic

nervous system

– ________ also regulate blood

pressure by controlling amount

of water in blood- when blood

pressure is high, more water

is__________; this reduces

blood volume

relaxes

Kidneys

removed

Blood Pressure

• Blood against the blood vessel’s walls

– The systolic pressure refers to

• the pressure recorded while the ventricles pump

the blood.

– The diastolic pressure refers to

• the pressure recorded as the ventricles fill with

blood.

• A normal blood pressure is 120/80

Blood Pressure

Blood Pressure

– High blood pressure

• forces heart to

___________

• people more likely to

develop heart disease

• obesity is one cause

• controlled by weight

control, exercise, and diet

work harder

Blood– Makes up 8% of body –

____ to___ liters

– Components of blood

• 45% = ____ blood cells,

______ blood cells and

platelets

• 55% = plasma

– mostly ________- 90%

– contains salts, sugars, and

plasma proteins

4 6

red

white

water

What does blood contain?

• 50% Water

• 45% Erythrocytes

• 4% Plasma with

Substances

• 1% Leukocytes +

• Platelets

Blood– Plasma proteins

• Several types of proteins that fight__________, regulate osmotic pressure & help blood ____________

– Red blood cells- erythrocyte- RBC• contain ________________- iron

containing protein that increases ___________ carrying ability of RBC’s

• produced in ______bone marrow

• mature RBC’s have no nucleus so can’t divide

• live about 120 days – when they die they are destroyed & recycled by spleen

infectionclotting

hemoglobin

oxygen

red

Blood– White blood cells – leukocytes- WBC

• fewer in numbers than RBC

• produced in bone marrow

• live for many months or years

• more than 20 different types

• guard against________________, fight_______________, and attack ________________

• an increase in the number of WBC’s is an indication the body is fighting an _____________________

– Platelets• fragments of cells

• when blood vessel is injured, platelets become sticky; they cluster around the wound and release a series of chemicals that start a clotting reaction

• a protein called __________forms a net that traps RBCs and forms a ______

infections pathogensbacteria

infection

fibrinclot

Blood Clotting

Break in Capillary Wall

Blood vessels injured.

Clumping of Platelets

Platelets clump at the site

and release thromboplastin.

Thromboplastin converts

prothrombin into thrombin..

Clot Forms

Thrombin converts

fibrinogen into fibrin, which

causes a clot. The clot

prevents further loss of

blood..

DISORDERS

• ATHEROSCLEROSIS

– Fatty deposits called plaque

– Builds up in walls of arteries

– Obstructs flow

– Also a risk if clot breaks free and blocks flow

elsewhere

Disorders (cont)

• Heart Attack

– Atherosclerosis in coronary artery

– Heart muscle begins to die

• Symptoms

– Nausea

– Shortness of breath

– Severe chest pain

IMMEDIATE MEDICAL ATTENTION NECESSARY

Disorders Continued

• Anemia

– Caused by either a deficiency of red blood

cells or hemoglobin in RBCs. Less oxygen

available for cells results in a lack of energy

due to decreased ATP production.

Disorders (cont)• Hypertension

– High blood pressure

– Hearts works harder than necessary

– Increases risk of heart attack or stroke

Disorders (cont)• Stroke (ADD TO NOTES)

– Blood clot gets stuck in blood vessels leading

to brain

– Brain cells die due to lack

of oxygen

• Or blood vessel burst

– Can lead to paralysis,

• loss of ability to speak

• death