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