CIRCULATORY SYSTEM

FUNCTIONS

Transports oxygen and nutrients to the cells

Transports carbon dioxide and other waste for elimination from the body

Maintains homeostasis of the body cells

3 MAIN PARTS

1. Heart

2. Blood

3. Blood vessels – arteries and veins*** Veins: carry blood back to the heart Arteries: carry blood from heart to body

tissues (when you take your pulse, you are checking one of these sights)

Capillaries: smallest blood vessels that connect the veins and arteries

SIMPLE VS. COMPLEX ANIMALS

Simple animals do NOT have a circulatory system. The exchange of materials and waste occur by diffusion across the main body cavity and cells. Example: Cnidarians

Complex Animals have either an open or closed circulatory system.

OPEN CIRCULATORY SYSTEM

The heart pumps blood into open-ended blood vessels.

The blood is pumped from the heart, through the vessels, and it “bathes” the tissues

Example: Grasshopper (Insects)

CLOSED CIRCULATORY SYSTEM

The hearts pumps the blood only through blood vessels which carry the blood to all the body tissues and then back to the heart.

Examples: Annelids, Mammals

Insect:Open Circulatory System

Annelid:Closed Circulatory System

Heartlikestructures

Bloodvessels

Heartlike structure

Small vessels in tissues

Bloodvessels

Hearts

Heart

Sinusesand organs

Open & Closed Circulatory Systems

Fish has a 2

chambered heart

Amphibian has a 3

chambered heart

Mammal has a 4

chambered heart

SINGLE LOOP VS. DOUBLE LOOP SYSTEM

2 CIRCUITS THAT BLOOD TRAVELS

(DOUBLE LOOP SYSTEM)1. PULMONARY CIRUIT: A short loop where

blood is carried between your heart and lungs. In your lungs the blood absorbs oxygen and releases carbon dioxide. Then the oxygenated blood returns to the heart.***

2. SYSTEMIC CIRCUIT: Carries oxygenated blood to all other body cells then the blood releases oxygen to the cells and picks up carbon dioxide and other wastes and returns to the heart.

Your heart is basically 2 pumps, one for each circuit.

Fish has a 2

chambered heart

Amphibian has a 3

chambered heart

Mammal has a 4

chambered heart

CHARACTERISTICS OF YOUR HEART

It is about the size of your fist. It is located beneath the sternum and

near the center of your chest. It is a hollow organ with thick walls

made of cardiac muscle. It is surrounded by a double walled sac

called the pericardium. It has 2 sides separated by a thick wall

called a septum. It has 4 chambers.

Figure 42.5 The mammalian heart: a closer look

Superior

PulmonaryTricuspid

Inferior

Aortic

Mitral

Septum

PARTS OF THE HEART AND THEIR FUNCTIONS

The atria (right atrium and left atrium) are at the top of the heart and the RECEIVE blood.

The Ventricles (right ventricle and left ventricle) are at the bottom of the heart and the PUMP BLOOD OUT.

Valves keep the blood moving in the correct direction.

The right side of the heart carries the deoxygenated blood.

The left side of the heart carries the oxygenated blood.

Figure 42.4 The mammalian cardiovascular system: an overview

Flow of blood through the heart:

Deoxygenated blood

right atriumright ventricle

pulmonary arterypulmonary vein

left atriumleft ventricle

aortabody

BLOOD PRESSURE

Caused by the force with which the ventricles contract.

Measured with a sphygmomanometer (blood pressure cuff)

A healthy adult should have a blood pressure of 120/80Top number is systolic pressure, the

force felt in the arteries when the ventricles contract

Bottom number is diastolic pressure, the force felt in the arteries when the ventricles relax.

BLOOD COMPONENTS

55% PLASMA (a straw colored fluid) 45% Blood Cells

Plasma 90% water 10% dissolved minerals

Blood cells Red blood cells- transport oxygen and get

their color from hemoglobin (an iron containing protein)***

White blood cells- fight disease Platelets- help in blood clotting

Watch This…

http://www.youtube.com/watch?v=KBIdcUxdgo0

Figure 42.14 The composition of mammalian blood