Unit D2: The Circulatory System T1-2

Circulatory System

the organs and tissues involved in circulating blood and lymph through the body

Functions of the circulatory system

Oxygen/Nutrients transport, pH/Temperature regulation, Defensive Mechanisms, Clotting and Healing

regulation of circulatory system

fluid balance, stabilizes pH, and temperature control

immune system

a complex response system that protects the body from bacteria, viruses, and other foreign substances

blood clotting

the process by which blood becomes thick and stops flowing, forming a solid cover over any place where your skin has been cut or broken.

platelets

thrombocytes, small blood fragment that collects at sites of injury to begin the clotting process

Heart

A hollow, muscular organ that pumps blood throughout the body.

Cardiovascular system

The heart and blood vessels, responsible for carrying oxygen and nutrients to the body through blood

blood

Connective tissue made of plasma, erythrocytes, leukocytes, and platelets.

white blood cells

leukocytes, function in the immune system; fights disease

red blood cells

erythrocytes, blood cells that carry oxygen from the lungs to the body cells.

closed circulatory system

A circulatory system in which the oxygen-carrying blood cells never leave the blood vessels. Mostly vertebrates, some invertebrates

open circulatory system

A circulatory system that allows the blood to flow out of the blood vessels and into various body cavities

artery

A blood vessel that carries blood away from the heart

vein

A blood vessel that carries blood back to the heart.

Capillaries

fine branching blood vessels that form a network between the arterioles and venules.

Arterioles

small vessels that receive blood from the arteries

Venules

small vessels that gather blood from the capillaries into the veins

Blood vessels

tubelike structures that carry blood throughout the body

vena cava

a large vein carrying deoxygenated blood into the heart

superior vena cava

receives blood from the head and arms and chest and empties into the right atrium of the heart

inferior vena cava

carries blood from lower regions of the body to right atrium of the heart

pulmonary vein

Deliver oxygen rich blood from the lungs to the left atrium

pulmonary artery

Carries deoxygentated blood from the heart to the lungs

descending aorta

carries blood away from the heart down the midline of the body

Aorta

The large arterial trunk that carries blood from the heart to be distributed by branch arteries through the body.

Common carotid artery

Supplies blood to the head and neck.

Pericardium

Fluid-filled double-layered membrane surrounding the heart, preventing friction

cardiomyocytes

Specialized contractile heart muscle cells

the heart wall

3 layers: epicardium, myocardium, endocardium

chambers of the heart

right atrium, right ventricle, left atrium, left ventricle

myocardium

muscular, middle layer of the heart

right atrium

Receives deoxygenated blood from the body

right ventricle

pumps deoxygenated blood to the lungs

left atrium

receives oxygenated blood from the lungs

left ventricle

pumps oxygenated blood to the body

striated

marked with thin, narrow grooves or channels

Ventricular septum

Divides the right and left chambers of the heart

pulmonary circulation

The path of blood from the right atrium through the right ventricle to the lungs and return to the left atrium

systemic circulation

circulation that supplies blood to all the body except to the lungs

Tricuspid valves

The atrioventricular valves between the right atrium and right ventricle.

right semilunar valve

Pulmonary valve, between right ventricle and pulmonary trunk

bicuspid/mitral valve

valve between the left atrium and the left ventricle

aortic arch

a curved blood vessel from which arteries branch to the head and neck.

left semilunar valve

between left ventricle and aorta, aortic valve

Valves

permit the flow of blood in one direction only

Atrioventricular valves

Valves between atria and ventricles, prevent backflow.

Semilunar valves

-Pulmonary and aortic valves

-Prevent backflow of blood into ventricles

thrombocytes

another name for platelets

Leukocytes

another name for white blood cells

Erythrocytes

another name for red blood cells

mitral valve

valve between the left atrium and the left ventricle; bicuspid valve

chordae tendineae

thin bands of fibrous tissue that attach to the valves in the heart and prevent them from inverting

systole

contraction phase of the heartbeat

Diastole

relaxation phase of the heartbeat, fills with blood

lub

closing of AV valves; at the beginning of ventricular systole

dub

caused by the closure of aortic and pulmonic valves, at the end of ventricular systole

ascending aorta

Branches off the left ventricle; carries oxygen rich blood to parts of the body above the heart

coronary arteries

blood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle

Venous return

blood returned to the heart by the veins

Myogenic

Describes muscle tissue that generates its own contractions.

sinoatrial node

"Pacemaker" in the right atrium, and that originates the electrical impulses through the atria, making them contract

atrioventricular node

Receives impulses from SA node, relays to purkinge fibres, located around right atrioventricular region

Purkinje fibers

fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract from the bottom up

The cardiac cycle

A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles

Stages of a cardiac cycle

atrial and ventricle diastole, atrial systole, ventricular systole

Atrial and Ventricular diastole

All chambers in diastole, decreased pressure allows blood to easily return from body and fill atria

Atrial systole

atrial contraction forces remaining additional blood into ventricles

ventricular systole

contraction of ventricles pushing blood into pulmonary arteries and aorta

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, blood pressure, and digestion.

Bundle of his

neurological fibers extending from the AV node that fire the impulse from the AV node to the Purkinje fibers

sympathetic nervous system

a set of nerves that prepares the body for action in challenging or threatening situations, increases heart rate

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy, slows heart rate

beats per minute

What heart rate is measured in

Apex

lower tip of the heart

Electrocardiogram (ECG)

recording of the electrical changes that occur in the myocardium during a cardiac cycle

arrhythmia

irregular heart rhythm

Myocardial infarction

a condition in which blood flow to part of the heart muscle is blocked, causing heart cells to die

bradycardia

abnormally slow heartbeat

P wave

depolarization of the atria

depolarization

Contraction of the heart

repolarization

Relaxation of the heart

QRS complex

ventricular depolarization

T wave

repolarization of ventricles

PR Interval

Time for impulse to travel from SA node to the ventricles

ST segment

time between ventricular depolarization and repolarization

heart murmur

an abnormal sound from the heart produced by defects in the chambers or valves

heart block

interference with normal conduction of electrical impulses that control activity of the heart muscle

pacemaker

A device that delivers electrical impulses to the heart to regulate the heartbeat

Tachycardia

Abnormally rapid heartbeat