A+P 2 Exam 1

Auricles

expand to provide more space for blood

Superior vena cava (SVC)

drains deoxygenated blood from most veins superior to the diaphragm (drains into posterior right atrium)

Inferior vena cava (IVC)

drains deoxygenated blood from most veins inferior to the diaphragm (drains into posterior right atrium)

Pulmonary trunk

receives deoxygenated blood from the right ventricle, located on the anterior side of the heart and splits into the right and left pulmonary arteries that bring deoxygenated blood to the lungs

Pulmonary Veins

oxygenated blood returns to the heart through four pulmonary veins, two from each lung that drain into posterior part of left atrium

aorta function

supplies the entire systemic circuit with oxygenated blood, largest and thickest artery in the body

Valves of the Heart

blood flow through the heart must occur in only one direction so two sets of valves prevent backflow

Atrioventricular Valves (AV)

valves between the atria and ventricles consists of flaps called cusps, composed of endocardium overlying extensions of the fibrous skeleton with rings surrounding the opening of the valves, "inflow" valves

Tricuspid Valve

between the right atrium and right ventricle, three cusps

Bicuspid (Mitral) Valve

Semilunar Valves: valves between the ventricles and the arteries, consist of three cusps with half-moon shapes, composed of endocardium and a thin layer of the fibrous skeleton with rings surrounding the opening of the valves, "outflow" valves.

Pulmonary Valve: between the right ventricle and pulmonary trunk

Aortic Valve: between the left ventricle and the aorta (no chordae tendineae or papillary muscles are present)

between the left atrium and left ventricle, two cusps

chordae tendineae

AV Valves supported, attach to papillary muscles to prevent cusps from everting back into the atria

Papillary Muscles

muscles in ventricles that connect to chordinae tendinae that control AV valves

Semilunar Valves

valves between the ventricles and the arteries, consist of three cusps with half-moon shapes, composed of endocardium and a thin layer of the fibrous skeleton with rings surrounding the opening of the valves, "outflow" valves.

Pulmonary Valve

between the right ventricle and pulmonary trunk

Aortic Valve

between the left ventricle and the aorta (no chordae tendineae or papillary muscles are present)

Epicardium

outermost layer composed of connective tissue (also called visceral pericardium)

Myocardium

middle layer, thickest, composed of muscle cells

Endocardium

deepest layer composed of endothelial cells that form blood brain barrier

Fibrous skeleton

Does not conduct a current, thick part between atria/ventricle, keeps atria and ventricles electrically separate, dense irregular connective tissue located in interventricular and interarterial septum and around heart valves. Gives cardiac muscle cells something to pull when contracted, provides structural support/insulator for electrical activity

Cardinomyocyte

make up heart muscle, striated like skeletal muscles that receive action potential from pace maker cells to depolarize and are connected by intercalated discs

Coronary Circulation

blood vessels that supply and drain the heart

Coronary Arteries

deliver oxygenated blood to the coronary capillary beds

Cardiac Veins

drain deoxygenated blood from the capillaries

The cardiac vein dump into coronary sinus which ultimately dumps into the right atrium

Left and Right Coronary Arteries

branch from the ascending aorta and travel in the right and left atrioventricular sulci respectively

Circumflex Artery

supplies the left atrium and parts of the left ventricle

Percutaneous Coronary Angiography

arteries can be images with this, small tube fed through systemic circuit and dye injected

Coronary Sinus

large venous structure on the posterior heart that drains into the right atrium

Anastomoses

systems of channels formed between blood vessels, may form between coronary arteries or with arteries outside the coronary circulation, little vessels that grow to make a bypass

Collateral Circulation

alternate routes of blood flow, if blood flow to the myocardium is insufficient

Role of Cardiac Conduction

1. The SA node generates an action potential, which spreads to atrial cells and AV node

2. After AV node delay, the action potential is conducted to the AV bundle and then to the right and left bundle branches

3. Action potential spreads from the bundle branches along the Purkinje Fibers to the contractile cells of the ventricles

Right side of heart

pumps blood to the lungs called pulmonary circuit

Steps of right side of heart

deoxygenated blood pumped to the lungs by right side of heart, gas exchange occurs between air in the alveoli and blood in pulmonary capillaries, oxygenated blood is returned to the left side of the heart

Left side of the heart

pumps blood to the rest of the body (besides the lungs)

Steps of left side of heart

Steps: oxygenated blood is pumped to body by left side of the heart, gas exchange occurs between tissues and blood in systemic capillaries, and lastly deoxygenated blood is returned to the right side of the heart

Autorhythmicity

cardiac muscle sets is own rhythm without a need for input from the nervous system

Contractile Cells

cardiac muscle cell that have intercalated discs and receive action potentials from pacemaker cells

Sinoatrial Node (SA)

located in the right atrium inferior and lateral to the opening of the superior vena cava, cells have the fastest intrinsic rate of depolarization of about 60-70 times per minute, influenced by parasympathetic and sympathetic system

Atrioventricular Node (AV)

cluster of pacemaker cells located posterior and medial to the tricupid valve, cells have a slower intrinsic rate of depolarization of about 40-50 times per minute

Purkinje Fiber System

slowest group of pacemaker cells that depolarize about 20 times per minute, action potentials rely on different ion channels called atypical pacemakers

Effective Refractory Period

time during which an excitable cell cannot be stimulated to contract again, very long in cardiac muscle compared to skeletal muscle

S1 Heart Sound

LUB - heard when the AV valves close (isovolumetric contraction phase)

S2 Heart Sound

DUB - heard when the SL valves close (isovolumetric relaxation phase)

Heart Murmur

caused by backflow of the valves

Electrocardiogram (ECG)

graphic depiction of the electrical activity occurring in all cardiac muscle cells over a period of time

Plateau phase

during part of an action potential when calcium ions will enter the contractile cell, when contractile cell has membrane potential of 0 mV

Occurs during the S-T segment after initial repolarization, before full repolarization

Pacemaker Cells

rhythmically and spontaneously generate action potentials, set hearts rhythm as they can spontaneously generate action potentials, part of electrocardiogram

Ions

go in and out relating to the pacemaker cells and their ion channels they have

Cardiac cycle

consists of one period of relaxation called Diastole and one period of contraction called systole for each chamber of the heart

Ventricular Filling Phase (P wave)

blood flows from atria to ventricles, mitral + tricuspid valves are open (ventricular diastole)

Isovolumetric Contraction Phase (QRS Complex)

ventricles contract with all valves closed, increases pressure without changing volume

Ventricular Ejection Phase (S-T Segment)

blood is ejected from ventricles, aortic and pulmonary valves (ventricular systole)

Isovolumetric Relaxation Phase (T- Wave)

ventricles relax with all values closed, decreased pressure without changing volume

P wave

atrial depolarization

QRS Complex

ventricular depolarization/atrial repolarization

T wave

ventricular repolarization

P-R Interval

duration of atrial depolarization and AV node delay (damage to the AV bundle or AV node will affect the duration of this interval)

S-T segment

ventricular plateau phase

Q-T Interval

ventricular cells are undergoing action potentials

R-R

heart rate

Cardiac Output 

HR x Stroke Volume

Stroke Volume

amount of blood pumped in one heartbeat

Subtract the amount of blood in the ventricle at the end of a contraction (ESV) from the amount of blood in the ventricle after it has filled during diastole (EDV)

May range from 50-120 mL

End-diastolic volume - End systolic volume

Typical End-Distolic Volume

110-120 mL

Typical End-Systolic Volume

30-60 mL

Cardiac Output

amount of blood pumped into the pulmonary circuit and systemic circuit in 1 minute

Preload

the stretch on the ventricles at the end of filling

Afterload

pressure the ventricles must overcome to eject blood

Affecting Factors

Preload imposed on the heart before it contracts, heart contractility or ability to generate tension, and afterload against which the heart pumps as it contracts

Cardiac Output Factors

hormones that increase cardiac output include aldosterone, antidiuretic hormone, and norepinephrine

Chronotropic Agents

factors that influence the rate at which the SA node depolarizes

Positive Agent

anything that increases the rate SA node fires (sympathetic, certain hormones, and elevated body temperature)

Negative Agent

anything that decreased the rate SA node fires (parasympathetic and decreased body temperature)

Inotropic Agents

agents that affect contractility

Bradycardia

heart rate under 60 beats per minute

Tachycardia

heart rate under 100 beats per minute

Artery

Blood goes away from heart

Elastic

largest diameter arteries, closest to the heart, have a lot of elastic fibers allowing them to stretch and accommodate high pressure from the hearts pumping

Muscular

also known as distributing arteries, medium-sized, mainly composed of smooth muscle cells, and include most named arteries that supply organs

Arteriole

smallest arteries with thin walls, control blood flow to tissues and feed capillary beds (smallest arterioles are called metarterioles)

Aorta

largest artery in the body, begins at the left ventricle and has four divisions

Ascending aorta

initial portion that travels superiorly, the right and left coronary arteries supply the myocardium branch

Aortic Arch

has three large branches that include brachiocephalic artery, left common carotid artery, and left subclavian artery

Descending Thoracic Aorta

supplies thoracic structures and enters the abdominopelvic cavity

Descending Abdominal Aorta

branches supply the abdominal viscera, right and left common iliac arteries and external iliac arteries

Veins

go towards the heart

Vein Valves

one-way, bicuspid, flap-like structures located within veins that prevent blood from flowing backwards against gravity.

Venous Valves

prevent blood from flowing backwards in the venous circuit

Blood reservoir

most blood is in the veins

Veins function as blood reservoirs and blood can be diverted from veins to other parts of the body because of their thin walls, fewer elastic fibers, less smooth muscle, and larger lumens than arteries.

Sinusoidal Capillaries

endothelial cells are a discontinuous sheet with an irregular basal lamina and very large pores, transfer large substances such as blood cells and larger proteins

Continuous Capillaries

endothelial cells joined by tight junctions

Fenestrated Capillaries

contain fenestrations (pores) in the endothelial cells, moderately leaky and allow large fluid and substance volumes

Precapillary sphincter

smooth muscle cells located at the junction of arterioles and capillaries, acting as valves to regulate blood flow into capillary beds

Capillary bed

branching vessels connect arterioles to venules, exchanging oxygen, nutrients, and waste between blood and tissues

Portal System

special types of circuit in which veins feed a capillary bed

Net filtration pressure

difference between colloid osmotic pressure and hydrostatic pressure gradient (NFP=HP-COP)

capillaries arteriolar end, NFP is 13mmHg, force drives water out capillary by filtration because hydrostatic pressure is greater at this end

capillaries venular end, NFP is -7mmHg, negative number means the water flows into the capillary, colloid osmotic pressure is greater

Vasa vasorum

network of microvessels (arterioles, capillaries, and venules), supply oxygen/nutrients to walls of large blood vessels

Tunic

The lumen of blood vessels are surrounded by several tissue layers or tunics (lumen is what the inside of a blood vessel is called)

Tunica Intima

composed of endothelium which is continuous with the inner lining of the heart (endocardium)

Tunica media

the middle layer composed of smooth muscle cells and elastic fibers, controls the diameter of the blood vessel and amount of blood that flows to organs

Tunica Externa (adventitia)

composed of dense irregular collagenous connective tissue that supports the blood vessel and prevents it from overstretching

Hydrostatic pressure

drives water out of the capillary, the force that fluid exerts on the wall of its contained blood pressure is equal to this (filtration)