Anatomy--Circulatory and Cardiovascular Systems Notes

The Circulatory SystemHeart, Blood, Blood Vessals

What is it?

A combination of

The cardiovascular system; Blood, heart, blood vessels

And the lymphatic system Lymph, lymph nodes, lymph vessels

Circulatory System

Simple animals (sponge, hydra) have no circulatory system

Complex animals have circulatory systems that are either:

Open – blood circulates inside the body without blood vessels

Closed – blood is inside vessels Humans have a closed system

Types of Circulatory Systems

The Human Heart

The heart is a muscle

It pumps blood through the body

There are upper and lower chambers on the two sides of the heart

The upper are called atria

The lower are called ventricles

Pumping of the Heart

Heart pumps 60-80 times a minute while you are resting

May pump up to 150 times a minute after running

Will pump more than 2 billion times in your lifetime

Heart Valves

For a pump to work right the liquid must go only in one direction

Valves are flaps in the heart that keep blood flowing in one direction

The tricuspid valve is between the right atrium and the right ventricle

The bicuspid valve is between the left atrium and the left ventricle

Heart Valves (cont.)

The other valves are the semilunar valves between the ventricles and their arteries.

If you listen to your heart you are hearing the main valves closing

Jobs of the Circulatory System

Main job is to pump oxygen from your lungs to the body

Right side of your heart pumps blood through the lungs

Blood from the lungs is pumped by the left side to all the parts of the body

Blood coming back from the body parts goes into the right side

Exchange of Gasses in the Lungs

More Jobs

Gets nutrients from the gastric system and distributes to the tissues

Gets wastes from the tissues and takes them to the lungs (CO2) and kidneys (waste chemicals)

Helps regulate temperature of the body More blood to the skin to lower temp Less blood to the skin to raise temp

Blood Vessels

You have about 60,000 Miles of blood vessels in your body (2.5 times around the world)

Three types of blood vessel Arteries – away from heart Capillaries – very small, one cell thick Veins – back to heart

Arteries

Carry blood away from the heart

Carry blood under high pressure

Round in shape and have thick, muscular walls

Veins

Carry blood to the heart

Carry blood under low blood pressure

They are flat in shape and have little muscle

They have one-way valves to keep blood flowing in one direction

Capillaries

Are very small and only one cell thick

Some blood cells can pass between the cells of the capillary wall

All the pickups (Carbon dioxide and waste) and deliveries (Oxygen and nutrients) occur in the capillaries