CHS anatomy chapter 11

Transportation

The major function of the cardiovascular system is

Inferior Mediastinum which is the medial cavity of the Thorax between the lungs

Where is the heart located in?

the apex

what is the bottom pointy part of the heart called?

Pericardium

The heart is enclosed by a double-walled sac

fibrous pericardium

is loose and superficial part of the sac

•This fibrous layer helps to protect the heart and anchors it to the surrounding structures: diaphragm & sternum

parietal pericardium

Outside layer that lines the inner surface of the fibrous pericardium

Visceral Pericardium

Next to heart; also known as the Epicardium and is actually part of the heart wall

Serous/pericardial fluid

a slippery lubricating fluid which fills the space between the layers of pericardium

Epicardium

Outside layer

•This layer is the visceral pericardium described above

•Rests on a Connective tissue layer

Myocardium

Middle layer

•Consists of thick bundles of cardiac muscle twisted in a ring-like arrangement

•It is the layer that contracts

•It is reinforced by fibrous connective tissue “Heart’s Skeleton”

•It contains:

•Tight junctions – bind the cells together

•Gap junctions – allows ions to move between cells

Endocardium

Inner layer

•A thin, glistening sheet of endothelium that lines the heart’s chambers

•This endothelium continues into the vessels and becomes the lining of the veins and arteries

Endocardium - lines the heart

Endothelium - lines the vessels

4

How many chambers does the heart have?

Two Atria

Superior Receiving chambers: Right & Left atrium

•The atria are not the pumping chambers, but instead, receive blood from the veins of the body under low pressure & then they release the blood through valves to fill the ventricles

•The atria are divided by the Interatrial septum

Two Ventricles

These chambers are thick walled and are the actual pumps of the heart

•When they contract, blood is propelled out of the heart and into the circulation

•The right ventricle forms most of the heart’s anterior surface and the left ventricle forms the apex

•The ventricles are divided longitudinally by the Interventricular septum

•Each of these chambers are lined with endocardium, which helps the blood flow smoothly through the heart

Veins

Carries blood towards the heart

Superior and Inferior Vena Cava

The right atrium of the heart receives oxygen-poor blood from_______which are the largest veins of the body

Pulmonary Trunk

The blood passes from the right atrium (through a valve) to the right ventricle & then the blood is pumped out of the heart; splits into the Pulmonary Arteries which carries the deoxygenated blood to the lungs where oxygen is picked up and carbon dioxide is unloaded

Arteries

Carries blood away from the heart

Brachiocephalic trunk

supplies the face, arms & brain

Left common carotid artery

supplies the brain

Left subclavian artery

supplies upper limbs

Systemic Circulation

Composed mostly of Arteries- Carries blood Away from the Heart

•The oxygenated blood returns to the left atria and it passes into the left ventricle (through a valve) after which, it is pumped out of the heart through the Aorta

•The aorta contains three branches which will carry oxygen rich blood to all of the body tissues

Pulmonary Curculation

Composed mostly of Veins – Carries blood towards the Heart

•The right atrium of the heart receives oxygen-poor blood from the Superior and Inferior Vena Cava which are the largest veins of the body

•The blood passes from the right atrium (through a valve) to the right ventricle & then the blood is pumped out of the heart through the Pulmonary Trunk

•The pulmonary trunk splits into the Pulmonary Arteries which carries the deoxygenated blood to the lungs where oxygen is picked up and carbon dioxide is unloaded (This is the only time deoxygenated blood will travel in an artery)

Pulmonary Arteries

carries the deoxygenated blood to the lungs where oxygen is picked up and carbon dioxide is unloaded (This is the only time deoxygenated blood will travel in an artery)

Pulmonary veins

The oxygenated blood is then returned to the left side of the heart through the ______

4

how many valves does the heart have?

Bicuspid (mitral) valve

located on the left side of the heart; It consists of two flaps or cusps of endocardium

It is apart of the Atrioventricular (AV) valves

Tricuspid valve

is located on the right side of the heart

*It consists of three flaps of cusps of endocardium

chordae tendinae

The valves are anchored in place by tiny white cords called

valves

•Allow blood to flow in only one direction to prevent backflow; open during heart relaxation, and close during ventricular contraction

Semilunar valves

These valves are located at the base of the large arteries leaving the ventricular chambers

•They are found between ventricle and artery

•Pulmonary semilunar valve

•Aortic semilunar valve

•Each valve has three leaflets that fit tightly together when the valves are closed

•They are closed during heart relaxation but open during ventricular contraction

•These valves operate opposite of one another to force a one-way path of blood through the heart

•When the AV valves are open, the SLV are not

coronary arteries

branch from the aorta to supply the heart muscle with oxygenated blood (AV Sulcus)

cardiac veins

drain the myocardium of blood (AV Sulcus)

Coronary sinus

a large vein on the posterior of the heart, receives blood from cardiac veins

•Deoxygenated Blood empties into the right atrium

6 liters 1000 times throughout the day

How many liters of blood does the heart pump throughout the body?

nope

Do heart muscles need to be stimulated my nerve impulses?

Nodal system

A system which is built into the heart tissue that sets the Basic Rhythm

•A special tissue found nowhere else in the body, which is like a cross between nervous and muscle tissue, sets the pace

Sinoatrial Node(SA node)

a crescent shaped node of tissue in the right atrium that acts like a pacemaker

Atrioventricular Node (AV node)

is at the junction of the atria and the ventricles

Atrioventricular Bundle

branches in the interventricular septum

Purkinje fibers

spread within the ventricle wall muscles

Increased Heart Rate

Apart of the Sympathetic nervous system of the ANS; Will stimulate the SA and AV nodes

If blood pressure is Low to get more oxygenatedblood to the body cells

Emergency, Exercise, Embarrassment & Excitement

b. Hormones

•Epinephrine/Adrenaline (produced by the adrenal gland)

•Thyroxine (produced in the Thyroid & responsible for metabolism)

c. Decreased blood volume

Decreased Heart Rate

Parasympathetic nervous system

*Primarily the Vagus nerves slow and steady the heart, giving it more time to rest during non-crisis times

b. High blood pressure or blood volume

c. Decreased venous return

d. Remember the “D”s : Digestion, Defecation & Diuresis

Heart Block

damage to the AV node can partially or totally releases the ventricle from the SA node’s control; this results in a slower heart rate as ventricles contract at their own rate

Ischemia

lack of adequate oxygen supply to heart muscle, this may lead to fibrillation

Fibrillation

a rapid, uncoordinated shuddering of the heart muscle.

•This makes the heart totally useless as a pump and is a major cause of death from heart attacks in adults

Tachycardia

rapid heart rate over 100 beats per minute

Bradycardia

slow heart rate less than 60 beats per minutes (treated with the implantation of a Pacemaker)

Cardiac Output(CO)

Amount of blood pumped by each side, 1 ventricle, of the heart in one minute ; SV x HR= CO

Stroke Volume (SV)

Volume of blood pumped by each ventricle in one contraction (each heartbeat)

•Usually remains relatively constant

•In general, SV increases as the force of ventricular contractions increase

•About 70 mL of blood is pumped out of the left ventricle with each heartbeat

Heart Rate (HR)

Typically 75 beats/minute; # of beats

Vascular System

Blood circulates inside the blood vessels, which form a closed transportation system, called the _______

•Just like roads, the vascular system has its highways, secondary roads and alleys

•The vascular system transports blood to the tissues and back

•Aorta

•Arteries

•Arterioles (largest-smallest)

Blood is carried away from the heart by?

Capillary beds

are only one cell layer (tunica intima) to allow for Exchanges/Diffusion between blood and tissue

•Venules

•Veins

•Vena Cava (smallest-largest)

Blood returns to the heart by?

Tunica intima

•Lines the Lumen or interior of the vessels

•It is a thin layer of Endothelium (Called Endocardium in the heart)

•Composed of Simple Squamous Epithelium resting on a basement membrane

•Has a slick surface that decreases friction as blood flows

Tunica media

A bulky middle coat composed of Smooth Muscle and Elastic fibers

•The muscle is controlled by sympathetic nervous system, which allows for the change in the vessel’s diameter

Tunica extrema

The outermost tunic layer

Composed mostly of Fibrous Connective Tissue

Supports and protects the vessels

veins

have a thinner tunica media than arteries

•The Lumen of veins are larger than arteries

•operate under low pressure

•To assist in the movement of blood back to the heart:

•Larger ____have valves to prevent backflow

•Skeletal muscle “milks” blood in veins toward the heart

arteries

Arteries have a thicker tunica media than veins

•Arterial blood is pumped from the heart, under High pressure

Aorta

•Largest artery in the body - diameter of your thumb

•Leaves from the left ventricle of the heart

Vena Cava

Unlike arteries which are deep, the veins tend to be more superficial

•Whereas the aorta branches into the major arteries, the capillary beds, venules and veins converge to form the superior and inferior vena cava

Superior Vena Cava

drains the head and arms

Inferior Vena Cava

drains the lower body

Pulse

The alternating expansion and recoil of an artery that occurs with each beat of the left ventricle creates a Pressure Wave of blood called a

Blood Pressure

is the pressure the blood exerts against the inner walls of the blood vessels

•Measurements of blood pressure by health professionals are made on the pressure in large arteries; Pressure in blood vessels decreases as distance from the heart increases

Systolic

pressure at the peak of ventricular contraction

Diastolic

pressure when ventricles relax

Renin

an enzyme released by the kidneys when BP is low. It causes vasoconstriction and increases BP

Atherosclerosis

or hardening of the arteries, is a condition in which plaque builds up inside the arteries. Plaque is made of cholesterol, fatty substances, cellular waste products, calcium and fibrin

Coronary artery disease (CAD)

is the most common type of heart disease. It is the leading cause of death in the United States in both men and women.

happens when the arteries that supply blood to heart muscle become hardened and narrowed.

*This is due to the buildup of cholesterol and other material, called plaque, on their inner walls.

Congestive heart failure (CHF)

is a chronic progressive condition that affects the pumping power of your heart muscles.

*While often referred to simply as “heart failure”, specifically refers to the stage in which fluid builds up around the heart causing it to pump inefficiently.

develops when your ventricles can’t pump blood in sufficient volume to the body. Eventually, blood and other fluids back up inside your: lungs, abdomen, liver, lower body