Mastering A & P Chapter 11

The root word ______ means pressure

-tension

Describe the events in the cardiac cycle

1. Atrial diastole (ventricular filling): AV valves open, semilunar valves closed, blood is flowing passively from atria to ventricle 2. Atria systole: Atria contracts forcing ventricular filling 3. Isovolumetric contraction: intraventricular pressure rises, AV valves close 4. Ventricular systole: semilunar valves open and blood is ejected from ventricles, atria is relaxed and filling with blood again 5. Isovolumetric relaxation: pressure in arteries is less than arteries, semilunar valves close, atria still is filling blood until pressure is greater than intraventricular pressure

Describe the factors influencing heart rate

1. sympathetic nervous system: times of fear and stress raises heart rate 2. parasympathetic nervous system: vagus nerve fibers slow down the heart rate 3. Hormones: epinephrine and thyroxine raises heart rate 4. Ions: Reduced ionic calcium levels depresses the heart 5. Age: Fetus has large heart rate, decreases as you age 6. Heat/exercises: also raise heart rate

Which of the following change produce the greatest change in total peripheral resistance

10% change in vessel diameter The main determinant of total peripheral resistance is the diameter of the small arterioles. As blood vessel diameter increases, resistance goes down, and vice versa. Resistance is inversely proportional to the fourth power of the blood vessel radius. Radius is one-half of the vessel diameter. This means any change in vessel diameter will affect resistance by a factor of 1/r4 where r is the radius. For example, a doubling of the vessel diameter will have a 2*2*2*2 or 16-fold reduction in resistance.

Identify structures associated with pulmonary circulation, hepatic circulation and systemic circulation

Pulmonary circulation - exchanges oxygen from air for carbon dioxide from tissues Hepatic circulation - Systemic circulation - exchanges carbon dioxide from tissues of the body for oxygen from the lungs. Systematic circulation also delivers nutrients to an removes waste from the tissues

An electrocardiogram (ECG) is a recording of the electric currents initiated in the heart by an electrocardiograph. What information can be determined from an ECG?

QRS complex, T wave, P wave

Explain the flow of blood through the cardiovascular system

Right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta -> body -> venae cavae

Differentiate between the right and the left heart chambers and valves

Right side pumps to lungs, left side pumps to whole body

The correct sequence of parts that function to carry cardiac impulses is

SA Node - AV Node - Atrioventricular bundle - Purkinje fibers.

T wave

The third wave that results from currents flowing during the repolarization of the ventricles

Right Ventricle Wall

Thicker than atria, but thinner than the left ventricle wall; only pumps blood to lungs

Left ventricle Wall

Thickest, since it must pump blood through the entire body

Atrial Walls

Thin-walled, as they collect and pump blood only a short distance

Three layers of the blood vessels

Tunic intima: endothelium Tunic media: smooth muscle that is controlled by the sympathetic nervous system Tunic externa: mostly fibrous connective tissue

What part of the heart's intrinsic conduction system carries impulses into the interventricular septum

atrioventricular (AV) bundle (bundle of His)

Pericardium cavity

contains the pericardial fluid that reduces friction between the myocardium and the pericardium

Pericardium

covers and protects the heart

During mid-to-late diastole, blood flows from the atria to fill their respective ventricles to prepare for systole. What is happening during this time?

a) Atrioventricular (AV) valves are open. b) Blood flows passively from veins through atria into ventricles. c) Atria contract to force the remaining blood into the ventricles.

Complete heart block

damaged AV node; no longer controlled by the SA node ---> results in a slower eart rate as ventricles contract at their own rate (incomplete heart block some beats still go through)

By what pathway does oxygen leave capillaries to supply body tissues?

diffusion through capillary cell membranes

Cardiac viens

drain the myocardium of blood

Which of these allows nutrient rich blood from the placenta to bypass the fetal liver and enter the inferior vena cava?

ductus venosus

During ____, the ventricles relax

early diastole

What are the three layers of the heart

epicardium, myocardium, endocardium

How does pressure in the vascular system vary?

from the highest starting in the aorta and the lowest ending in the vena cavae

The root word ______ means liver

hepat-

During _____, the ventricles fill with blood

mid-to-late diastole

The membrane surrounding the heart is the

pericardium

What is the function of the heart valves?

prevents backflow of blood

Tachycardia

rapid heart rate over 100 beats per minute

What is the venus system?

returns unoxygenated blood to left atrium

The root word ______ means hard

scler-

Describe how the heart nourishes itself

since the blood in the heart does not nourish the myocardium, it maintains its own system of coronary arteries, cardiac veins, and coronary sinus • blood empties into the right atrium via the coronary sinus

State the sequence of the cardiac conduction system

sineatrial (SA) node -- impulse goes through atrial myocardium to atrioventricular node (impulse delayed to give atria time to finish contracting) -- atria contracts -- AV bundle -- bundle branches -- purkinge fibers -- contraction of ventricles starting at the apex to the atria

Bradycardia

slow heart rate less than 60 beats per minute

Which of these describes a fenestrated capillary?

special capillary type with small pores found in tissue where absorption is important

Which of these will decrease heart rate

stimulation of vagus nerve

From what organs does the hepatic portal vein receive blood?

stomach, intestine, spleen, and pancreas

During ____, the ventricles contract

systole

Total peripheral resistance

the amount of friction blood encounters during flow through blood vessels

Blood Pressure

the force of the blood against the vessel wall

Blood viscosity

the friction red blood cells encounter when moving past each other.

Where is most of the body's blood filtered through?

the liver

Sinoatrial (SA) node

the mass of specialized myocardial cells in the wall of the right atrium; pacemaker of the heart

Purkinje Fibers

the modified cardiac muscle fibers of the conduction system of the heart that carry impulses to the myocardium

Hepatic Portal System

the veins that carry blood from the digestive organs to the liver

Cardiac Output

the volume of blood pumped out by one ventricle each minute

Through which valve will blood flow when leaving the right atrium

tricuspid valve

Atrioventricular (AV) node

two valves set between atria and ventricles to prevent backflow; includes the mitral (bicuspid) on the left and the tricuspid on the right

Which of the following with slow the heart rate

vagus nerve stimulation

Name one action that helps move blood through the veins

valves and capillaries

The root word ______ means vessel

vas-

A surgeon who repairs damaged blood vessels is called a

vascular surgeon

Stroke volume

• The amount of blood ejected from the heart in one contraction. • usually remains relatively constant • about 70 mL of blood is pumped out of the let ventricle with each heartbeat

Coronary sinusterm-61

• a large veins on the posterior of the heart, receives blood from cardiac veins • blood empties into the right atrium via the coronary sinus

State the influences effecting cardiac output

• automatic nervous system • atrial and ventricular reflexes • hormones/physical factors • blood ion concentrations

Conduction system in heart

• causes heart muscle depolarization in only one direction, from the atria to the ventricles • enforces a contraction rate of 75 beats per minute

myocardium

• consists of thick bundles of cardiac muscle twisted and whorled into ringlike arrangements • the actual heart muscle itself • middle layer

Capillary beds

• consists of two types of vessels --> Vascular Shunt: vessel directly connecting an arteriole to a venule --> True Capillaries: exchange vessels • oxygen and nutrients cross to cells • carbon dioxide and metabolic waste products cross into blood

skeletal muscle pump

• contractions of skeletal muscles squeeze veins and move blood along

What is the function of the cardiovascular system?

• delivers oxygen and nutrients to the body tissues and carries away wastes such as carbon dioxide via blood • distributes blood to all part of the body

Systemic Circulation

• exchanges carbon dioxide from tissues of the body for oxygen from the lungs. Systematic circulation also delivers nutrients to an removes waste from the tissues • blood flows from the left side of the heart through the body tissues and back to the right side of the heart

Pulmonary Circulation

• exchanges oxygen from air for carbon dioxide from tissues • blood flows from the rights side of the heart to the lungs back to the left side of the heart • from lungs and then back to the right atrium • results in the transition of deoxygenated blood to oxygenated blood

Epicardium

• is the thin outer layer of the heart • the innermost layer of the pericardium and the outermost layer of the heart wall • connective tissue layer

Endothelial cells

• line the entire circulatory system from the heart to the smallest capillaries

Describe the hepatic portal circulation

• liver receives venous blood from the GI tract through the hepatic portal vein • Spleen and pancreas also drain via venous system to the liver • Venous blood is rich in substances absorbed from GI tract • Liver processes the absorbed substances before passing into general circulation to keep nutrient levels sable throughout the body • liver also gets oxygenated blood from hepatic artery • liver helps maintain proper glucose, fat, and protein concentration in blood

Valves: Atrioventricular (AV) valves

• located between atria and ventrcles • open during heart relaxation and closed during ventricular contraction •-->Tricuspid valve (right side of the heart) •-->Bicuspid (MITRAL) valve (left side of the heart)

Semilumar valves

• located between ventricle and artery • closed during heart relaxation but open during ventricular contraction •--> Pulmonary semilunar valves (right atrium to Rt & Lt pulmonary arteries-unoxygenated blood) •--> Aortic semilunar valve (left ventricle to aorta)

Endocardium

• part that touches the blood as it moves • lines the inner chambers of the heart • endothelium

respitory pump

• pressure changes in the thoracic and abdominal cavities during breathing squeeze the abdominal veins and move blood through them

venous aids for the return of blood to the heart

• skeletal pump and respiratory pump • to assist in the movement of blood back to the heart --> larger veins have valves to prevent backflow --> skeletal muscle "milks" blood in veins toward the heart

Know how the heart receives it supply of oxygen and how wastes and carbon dioxide are removed

• the blood vessels transport blood to the tissues and back ---> arteries (aorta main artery leaving the heart) and arterioles carry blood away from the heart (oxygenated) • exchanges between tissues and blood w the capillary beds ---> the veins and venules return blood toward the heart (unoxygenated) *The one exception in the vascular system is pulmonary arteries( unoxygenated blood) and pulmonary veins (oxygenated blood) • smooth muscle in the lumen artery is thicker so blood from the aorta will have a higher pressure

intercalated discs

• unique to cardiac • are thickenings of plasma membrane where two cardiac cells come together. They hold the calls together and contain gap junctions

___is lower than normal blood pressure

Hypotension

Which type of vessel has a thick tunica media?

artery

Ischemia

lack of adequate oxygen supply to heart muscle

What chamber of the heart will blood enter after passing through the bicuspid valve

left ventricle

inferior vena cava

A vein that is the largest vein in the human body and returns blood to the right atrium of the heart from bodily parts below the diaphragm.

Superior Vena Cava

A vein that is the second largest vein in the human body and returns blood to the right atrium of the heart from the upper half of the body such as the head and arms

Circle of Willis

Anterior and posterior blood supplies are united by small communicating arterial branches • Result --> complete circle of connecting blood vessels called cerebral arterial circle or circle of Willis

Distinguish between the anatomical structures of arteries, arterioles, capillaries, veins, and venules

Arteries • Aorta: leaves left ventricle to circulation • Pulmonary arteries: leaves right ventricle to the lungs Veins • Superior and inferior venae cavae • enter right atrium from the circulation • coronary sinus drains venous blood supply from the heart circulation • Four pulmonary veins from the lungs enters into left atrium

Describe blood flow during systole and diastole

During systole the ventricles contract. During mid to late diastole, the ventricles fill with blood. During early diastole, the ventricles relax

Differentiate between the flow flow of blood within cardiac circulation and coronary heart blood flow

Heart muscle (myocardium) has its own blood supply and specific path to bring blood back into the general circulation

Why does the cardiovascular system work?

If the cardiovascular system cannot perform its functions, wastes build up in tissues. Body organs fail to function properly and then once oxygen becomes depleted they will die

What increases blood pressure

Increase blood viscosity Increase cardiac output Increase blood volume Increase total peripheral resistance Increase blood vessel length

Diastolic Pressure

Indicates blood pressure at its low point when the ventricles relax and minimal pressure is exerted against the vessel walls

Systolic Pressure

Indicates the highest blood pressure when the ventricles of the heart contract and force blood into the aorta

Arterial Supply of the brain

Internal carotid arteries divide into --> Anterior and middle cerebral arteries; supply most of the cerebrum These arteries supply most of the cerebrum • Vertebral arteries join once within the skull to form the basilar artery • Basilar artery serves the brain stem and cerebellum • Posterior cerebral arteries form from the division of the basilar artery • These arteries supply the posterior cerebrum

During ventricular systole, high pressure in the ventricles pushes blood through the respective arteries. Atria and ventricles cannot contract at the same time, so the atria are in diastole during ventricular systole. What is the process?

Intraventricular pressure begins to increase -> Atrioventricular (AV)valves close -> Isovolumetric contraction occurs -> Intraventricular pressure rises above arterial pressure -> Semilunar valves open -> Ventricular ejection occurs.

Major Veins of Systemic Circulation

Superior and inferior vena cava enter the right atrium of the heart •Superior vena cava drains the head and the arms • Inferior vena cava rains the lower body

What action occurs that forces arterial blood to travel through the circulatory system?

The atria contracts to force the remaining blood into the ventricles

P wave

The first wave on an ECG that follows the firing of the SA node. This wave is small and signals the depolarization of the atria immediately before they contract.

How does the cardiovascular system work?

The heart pumps blood though out the body in blood vessels. Blood flow requires both the pumping action of the heart and changes in blood pressure

QRS Complex

The large wave that results from the depolarization of the ventricles and precedes the contraction of the ventricles.

Valves

allow blood to flow in only one direction to prevent backflow 4 valves

Blood pressure would increase as a result of a decrease in

blood vessel diameter Decreases in blood vessel diameter increase blood pressure because blood has more difficulty flowing through small vessels than large vessels. In other words, a decrease in blood vessel diameter increases total peripheral resistance. Assuming cardiac output remains constant, the increased total peripheral resistance would increase blood pressure. Or perhaps more intuitively, if cardiac output is to remain constant, blood pressure must increase.

Coronary arteries

branch from the aorta to supply the heart muscle with oxygenated blood

The root word ______ means heart

cardi-

What decreases blood pressure

increasing blood vessel diameter

Which arteries carry oxygen rich blood into the cranial cavity?

internal carotid arteries and vertebral arteries