A&P 2 Unit 2 Study Guide

Describe the phases of the cardiac cycle and relate them back to the events of the EKG. (essay)

1. Ventricular filling a. passive: occurs before the P wave where blood passively flows from the atria through open valves and slowly fills the ventricles b. active: occurs between P and Q. Atria contract and squeeze blood into the ventricles 2. Ventricular systole a. contraction: at S. Ventricles contract and build pressure to open the SL valves b. ejection: between S and T: blood is ejected from the ventricles to fill the aorta and pulmonary trunk 3. Ventricular relaxation: occurs after T wave. Ventricles relax and prepare to fill with blood

contractile cardiac muscle action potentials

1. depolarization 2. plateau phase 3. repolarization

parts of an action potential in typical pacemaker cells (3)

1. pacemaker potential 2. depolarization 3. repolarization

artery & vein tunics (3)

1. tunica intima (interna) 2. tunica media 3. tunica externa

heart rate

A measure of cardiac activity usually expressed as the number of beats per minute.

A-

Antigen on red blood cells: A Antibodies in plasma: anti-B Rh factor: negative Can receive blood from: A-, O- Can donate blood to: A+, A-, AB+, AB-

A+

Antigen on red blood cells: A Antibodies in plasma: anti-B Rh factor: positive Can receive blood from: A+, A-, O+, O- Can donate blood to: A+, AB+

AB-

Antigen on red blood cells: A & B Antibodies in plasma: none Rh factor: negative Can receive blood from: A-, B- AB-, O- Can donate blood to: AB+, AB-

AB+

Antigen on red blood cells: A & B Antibodies in plasma: none Rh factor: positive Can receive blood from: universal recipient Can donate blood to: AB+, AB-

B+

Antigen on red blood cells: B Antibodies in plasma: anti-A Rh factor: positive Can receive blood from: B+. B-, O+, O- Can donate blood to: B+, AB+

B-

Antigen on red blood cells: B Antibodies in plasma: anti-A Rh factor: negative Can receive blood from: B-, O- Can donate blood to: B+, B-, AB+, AB-

O-

Antigen on red blood cells: none Antibodies in plasma: anti-A & anti-B Rh factor: negative Can receive blood from: O- Can donate blood to: universal donor

O+

Antigen on red blood cells: none Antibodies in plasma: anti-A & anti-B Rh factor: positive Can receive blood from: O+, O- Can donate blood to: A+, B+, AB+, O+

cardiac output & blood pressure

Anything that decreases CO also decreases BP because there is less pressure on the walls.

step 1 (normal ECG)

Atrial depolarization, initiated by the SA node, causes the P wave.

What is cardiac output? What is the equation? What factors affect both parts of the equation? (essay)

Cardiac output the amount of blood pumped from each ventricle in one minute. The equation is Cardiac Output = Heart Rate X Stroke Volume (CO=HR X SV). The heart rate is affected by innervation of the autonomic nervous system which includes the sympathetic cardioacceleratory and the parasympathetic cardioinhibitory centers of the medulla oblongata. The sympathetic cardioacceleratory center of the medulla oblongata stimulates the heart, innervates SA node, AV node, myocardium , and coronary arteries to increase the heart rate and force. The parasympathetic cardioinhibitory center of the medulla oblongata inhibits the heart, stimulates vagus nerve, maintains vagal tone (sinus rhythm at 70=80 bpm). Stroke Volume is the amount of blood leaving the heart in one heart beat. It is affected by preload (amount ventricles are stretched by blood before they contract), afterload (back pressure exerted by blood in the large arteries leaving the heart), and contractility (contraction force for a given preload contraction force). Sympathethic activity affects both Heart Rate and Stroke Volume.

Describe the intrinsic conduction system and its parts.

It coordinates heart activity by determining the direction and speed of heart depolarization. -SA (sinoatrial) node -AV (atrioventricular) node -AV bundle -Bundle Branches -Purkinje fibers

Describe the regulation of blood pressure, including neural control, involvement of hormones and other chemicals, and contribution by the kidneys. (essay)

The following mechanisms help regulate blood pressure: -The cardiovascular center, located in the medulla oblongata, provides a rapid, neural mechanism for the regulation of blood pressure by managing cardiac output or by adjusting blood vessel diameter. -----The cardiac center stimulates/inhibits cardiac output by increasing/decreasing heart rate. These nerve impulses are transmitted over sympathetic cardiac/parasympathetic vagus nerves. -----The vasomotor center regulates blood vessel diameter. -The cardiovascular center receives information about the state of the body through baroreceptors (sensory neurons that monitor arterial blood pressure) and chemoreceptors (sensory neurons that monitor levels of CO2 and O2). The cerebral cortex, hypothalamus, and limbic system also send signals when blood pressure needs to be adjusted. -The kidneys provide a hormonal mechanism by managing blood volume. -----The renin‐angiotensin‐aldosterone system has two mechanisms that increase blood pressure by increasing blood volume. ----------Angiotensin II constricts blood vessels throughout the body as well as stimulates the adrenal cortex to secrete aldosterone, which increases the retention of H2O and Na+ by the kidneys. -----Epinephrine and norepinephrine, which are secreted as part of the fight-or-flight response, increase heart rate contractility and cause vasoconstriction. -----Antidiuretic hormone (ADH) raises blood pressure by stimulating the kidneys to retain H2O. -----Atrial natriuretic peptide (ANP) causes vasodilation and stimulates the kidneys to excrete more water and Na+. -----Nitric oxide (NO) causes vasodilation. -----Nicotine raises blood pressure. -----Alcohol lowers blood pressure.

step 3 (normal ECG)

Ventricular depolarization begins at the apex causing the QRS complex. Atrial repolarization occurs.

step 4 (normal ECG)

Ventricular depolarization in complete.

step 5 (normal ECG)

Ventricular repolarization begins at the apex, causing the T wave.

step 6 (normal ECG)

Ventricular repolarization is complete.

Tunica interna (tunica intima)

- Endothelial layer that lines the lumen of all vessels: simple squamous cells overlying loose ct. - Reduces friction, selectively permeable barrier

Tunica media

- Smooth muscle and elastic fiber layer, regulated by sympathetic nervous system - strengthens vessel and prevents blood pressure from rupturing them - Controls vasoconstriction/vasodilation of vessels

preload

- amount ventricles are stretched by blood before they contract ↑ preload causes ↑ contraction strength -affects stroke volume

autorhythmic cells

-1% of heart -Initiate action potentials that spread throughout the heart to trigger a rhythm -Have unstable resting potentials called pacemaker potentials -Use calcium influx (rather than sodium) for rising phase of the action potential

Capillary Blood Pressure

-Capillary BP ranges from 20 to 40 mm Hg -Low capillary pressure is desirable because high BP would rupture fragile, thin-walled capillaries -Low BP is sufficient to force filtrate out into interstitial space and distribute nutrients, gases, and hormones between blood and tissues

Tunica externa

-Collagen fibers that protect and reinforce vessels -often merges with that of neighboring blood vessels, nerves, or other organs -anchors the vessel and provides passage for small nerves, lymphatic vessels -Larger vessels contain vasa vasorum: small vessels that supply blood to at least the outer half of the larger vessels

Fenestrated Capillaries

-Found wherever active capillary absorption or filtrate formation occurs (e.g., small intestines, endocrine glands, and kidneys) - Characterized by: --An endothelium riddled with pores (fenestrations) --Greater permeability than other capillaries

transport (blood function)

-Gases, namely oxygen (O2) and carbon dioxide (CO2), between the lungs and rest of the body -Nutrients from the digestive tract and storage sites to the rest of the body -Waste products to be detoxified or removed by the liver and kidneys -Hormones from the glands in which they are produced to their target cells -Heat to the skin so as to help regulate body temperature

Sinusoids

-Highly modified, leaky, fenestrated capillaries with large lumens -Found in the liver, bone marrow, spleen, lymphoid tissue, and in some endocrine organs -Allow large molecules (proteins and blood cells) to pass between the blood and surrounding tissues

protection (blood function)

-Leukocytes, or white blood cells, destroy invading microorganisms and cancer cells -Antibodies and other proteins destroy pathogenic substances -Platelet factors initiate blood clotting and help minimise blood loss

components of blood

-Plasma -Erythrocytes, also known as red blood cells (RBCs) -Leukocytes, also known as white blood cells (WBCs) -Platelets

Continuous Capillaries

-abundant in the skin and muscles -Endothelial cells provide a continuous tube -Adjacent cells are connected with tight junctions -Intercellular clefts allow the passage of fluids

venous return

-aided by the muscular and respiratory pumps -valves prevent backflow

hemolytic disease (newborn)

-anti-Rh antibodies produced by the mother pass through the placenta, which attack red blood cells, and destroy good cells -can cause the newborn to have anemia or other conditions, such as elevated bilirubin levels and inability to fight off infection

coronary arteries

-arise from the base of the aorta and encircle the heart in the coronary sulcus -provide the arterial supply of the coronary circulation

arteries vs. veins

-arteries are larger, more muscular and more elastic -arteries carry blood that is under pressure from having been pumped out of the heart -veins are under much less pressure, so they are not as strong

blood vessels

-arteries, capillaries, and veins -carry blood (oxygen, nutrients and wastes) through the body

afterload

-back pressure exerted by blood in the large arteries leaving the heart -affects stroke volume

depolarization (pacemaker cells)

-begins when the pacemaker potential reaches tghreshold -due to Ca2+ influx through Ca2+ channels

pericardial cavity

-between parietal and visceral layers -contain a film of serous fluid

pulmonary trunk

-blood pumped from right ventricle -routes blood to lungs

veins

-carry blood toward the heart -greater capacity for blood containment than arteries -thinner walls, flaccid, less muscular and elastic tissue -collapse when empty, expand easily -have steady blood flow -merge to form larger veins -subjected to relatively low blood pressure

coronary veins

-collects venous blood -paths roughly follow those of the coronary arteries -join to form the coronary sinus

capillaries

-contact tissue cells and directly serve cellular needs...gas exchange -composed of endothelium with sparse basal lamina -Walls consisting of a thin tunica interna, one cell thick - Allow only a single RBC to pass at a time

contractility

-contraction force for a given preload -affects stroke volume

serous pericardium

-deep to fibrous pericardium -thin, slippery two-layer serous membrane that forms a closed sac around the heart

AV (atrioventricular) node

-delays while the atria of the heart contract -impulse arrives from SA Node -action potentials are transmitted more slowly in these cells than in other cells of the conduction system

factors influencing stroke volume

-determined by force of contraction in ventricular myocardium -influenced by contractility and length tension relationship of muscle fibers

factors influencing heart rate

-determined by rate of depolarization in autorhythmic cells -slowed by parasympathetic innervation -is made faster by sympathetic innervation

repolarization (contractile cardiac muscle)

-due to Ca2+ channels inactivating and K+ channels opeing -allows K+ efflux, which brings it back to resting voltage

repolarization (pacemaker cells)

-due to Ca2+ channels inactivating and K+ channels opening -allows K+ efflux, which brings the membrane potential back to its most negative voltage

plateau phase (contractile cardiac muscle)

-due to Ca2+ influx through slow Ca2+ channels -most K+ channels are closed

depolarization (contractile cardiac muscle)

-due to Na+ influx through fast voltage-gated Na+ channels -channel inactivation ends this phase

visceral layer (serous pericardium)

-external heart surface -also called the epicardium

pericardium layers

-fibrous pericardium -serous pericardium

ST Segment

-gap (flat or slightly upcurved line) between the S wave and the T wave -represents the time between ventricular depolarization and repolarization.

athlete

-healthy heart -strong SV -low HR

erythropoiesis (organs, tissues, and hormone)

-hemoglobin -erythropoetin -kidney -liver -bone marrow

QRS Complex

-indicates ventricular depolarization and contraction (ventricular systole) -Q and S waves are downward waves -R wave, an upward wave, is the most prominent feature of an ECG

causes of circulatory shock

-large-scale blood or fluid loss due to hemorrhage, vomiting, diarrhea, or extensive burns -poor circulation due to extreme vasodilation -loss of vasomotor tone due to anaphylaxis -failure of autonomic nervous system regulation -septicemia -pump failure due to myocardial damage from heart attacks

parietal layer (serous pericardium)

-lines the internal surface of the fibrous pericardium -attaches to large arteries exiting the heart

AV bundle

-links between atria and ventricle -impulse travels through after leaving the AV node

mitral (bicuspid) valve

-located between left atrium and left ventricle -prevents backflow into the atrium when the ventricle contracts

tricuspid valve

-located between right atrium and right ventricle -prevents backflow into the atrium when the ventricle contracts

pulmonary semilunar valve

-located between right ventricle and pulmonary trunk -prevents blood from flowing back into the right ventricle

aortic semilunar valve

-located between the aorta and left ventricle -prevents blood from flowing back into the left ventricle

fibrous pericardium

-loosely fitting -superficial -protects the heart -anchors heart to surround structures -prevents overfilling of the heart with blood

Diastolic pressure (Arterial Blood Pressure)

-lowest level of arterial pressure during a ventricular cycle -sensitive to peripheral resistance (rate of blood flow leaving the systemic arteries)

lub sound (heart sounds)

-made first -Caused by turbulence from closing of mitral and tricuspid valve during the start of systole

dub sound (heart sounds)

-made second -Caused by closure of from the aortic and pulmonic valves at the end of systole

hemorrhage

-massive loss of blood -decreases BP and CO

plasma

-mixture of water, sugar, fat, protein and salts -transports blood cells throughout the body along with nutrients, waste products, antibodies, clotting proteins, chemical messengers, and proteins that help maintain the body's fluid balance

peripheral resistance (PR)

-opposition to flow -three sources are blood vessel length, blood viscosity, and blood vessel diameter -the longer the blood vessel length, the greater the amount encountered -frequent vessel diameter changes significantly alter it

regulation (blood function)

-pH by interacting with acids and bases -Water balance by transferring water to and from tissues

Systolic pressure (Arterial Blood Pressure)

-pressure exerted on arterial walls during ventricular contraction -sensitive to cardiac output

blood viscosity

-refers to the stickiness of blood -increased with polycythemia and dehydration slows blood flow -decreased with anemia and hypoproteinemia speeds blood flow

Arterial Blood Pressure

-reflects the elasticity (compliance or distensibility) of arteries close to the heart -reflects the amount of blood forced into arteries close to the heart at any given time -is pulsatile (BP rises and falls)

Systemic Blood Pressure

-results when flow is opposed by resistance -is highest in the aorta -declines throughout the length of the pathway -steepest change occurs in the arterioles

SA (sinoatrial) node

-sets pace for entire heart, the pacemaker that initiates every heart beat by generating impulses -where an action potential is initiated and travels by way of conduction fibers to the AV node

prepotentials (pacemaker potentials)

-spontaneously changing -initiate the action potentials that spread throughout the heart to trigger its rhythmic contractions

Venous Blood Pressure

-steady and changes little during the cardiac cycle -pressure gradient is only about 20 mm Hg (the lowest)

similarities between cardiac and skeletal muscle

-striated -contract in the same way (sliding filament) -contain mitochondria, T tubules, sarcoplasmic reticulum -use ATP -use Ca2+ to bind to troponin

cardiac output

-the amount of blood pumped from each ventricle in one minute -product of heart rate and stroke volume

pulmonary vs. systemic circulation

-the two circulatory pathways of the vascular system -pulmonary circulation: short loop that runs from the heart to the lungs and back to the heart -systemic circulation routes blood through a long loop to all parts of the body and returns to the heart

pulmonary veins

-transport blood from the lungs back to the heart -enter left atrium

autonomic nervous system cardiac output control

-vagus nerve (parasympathetic) decreases heart rate -sympathetic cardiac nerves increase heart rate and force of contraction

heart patient (de-conditioned person)

-weak heart -weak SV -high HR (increases to compensate)

myocardial contraction and action potential

1. Na+ channels open 2. Rapid depolarization 3. Na+ channels close 4. Slow Ca2+ channels open 5. K+ channels open, but Ca2+ still entering so K+ permeability drops 6. Ca2+ channels close and repolarization occurs

sequence of electrical excitement (intrinsic cardiac conduction system)

1. The sinoatrial (SA) node (pacemaker) generates impulses. 2. The impulses pause (0.1 s) at the atrioventricular (AV) node. 3. The atrioventricular (AV) bundle connects the atria to the ventricles. 4. The bundle branches conduct the impulses through the interventricular septum. 5. The subendocardial conducting network depolarizes the contractile cells of both ventricles.

hemostasis steps

1. Vascular Spasm - damaged blood vessels respond to injury by constricting. 2. Platelet Plug Formation - platelets stick together to form a temporarily seal on the break. 3. coagulation - Fibrin forms a mesh that traps red blood cells and platelets.

step 2 (normal ECG)

With atrial depolarization complete, the impulse is delayed at the AV node.

vasoconstriction

a change in vessel radius by muscular effort that results in smooth muscle contraction

vasodilation

a change in vessel radius by relaxation of the smooth muscle

Blood pressure

a measure of the force being exerted on the walls of arteries as blood is pumped out of the heart

stroke volume

amount of blood pumped out of a ventricle during one contraction

circulatory shock

any condition in which blood vessels are inadequately filled and blood cannot circulate normally

platelets

assist coagulation by gathering at the site of an injury, sticking to the lining of the injured blood vessel, and forming a platform on which blood coagulation can occur

vascular system

blood is : --> propelled into large arteries leaving the heart --> enters smaller arterioles which feed capillary beds --> capillary beds drain into venules --> venules empty into veins --> veins empty into the right atria of the heart

arteries

carry blood away from the heart

Purkinje fibers

carry the contraction from the Bundle Branches to throughout the ventricles

lumen

central blood-containing space surrounded by tunics

right ventricle

chamber that receives blood from the right atrium and pumps it into the pulmonary artery

left ventricle

chamber that receives oxygenated blood and pumps it out to the body

coronary sinus

collects blood draining from the myocardium

erythrocytes (red blood cells)

contain hemoglobin which helps carry oxygen from the lungs to the rest of the body and then returns carbon dioxide from the body to the lungs so it can be exhaled

structural types of capillaries (3)

continuous, fenestrated, and sinusoids

muscular pump

contraction of skeletal muscles "milk" blood toward the heart...exercise and posture become important

Bundle Branches

convey impluses through the ventricular walls to the Purkinje fibers

pericardium

double-walled sac that encloses the heart

What are other influences over cardiac output?

heart rate and stroke volume

T Wave

indicates ventricular repolarization, in which the ventricles relax following depolarization and contraction

P Wave

indicating atrial depolarization in which the atria contract (atrial systole)

aorta

largest artery in the body

serous pericardium layers

parietal & visceral

respiratory pump

pressure changes created during breathing; inhale--> thoracic cavity expands, pressure decreases, abdominal pressure increases, forcing blood upward

leukocytes (white blood cells)

protect the body from infections

superior vena cava

returns blood from body area superior to the diaphragm

inferior vena cava

returns blood from body areas below the diaphragm

Trace one drop of blood from the right atrium until it enters the aorta. This pathway best describes which circuit? Trace a drop of blood from the aorta all the way to the right atrium. Which circuit is described by this route? (essay)

right atrium--> tricuspid valve--> right ventricle--> pulmonary semilunar valve--> pulmonary trunk--> pulmonary arteries--> capillary beds of lungs lungs--> pulmonary veins--> left atrium--> bicuspid valve--> left ventricle--> aortic semilunar valve --> aorta This pathway best describes the pulmonary circuit. aorta (3 branches) --> body (arteries to capillaries to veins)--> venae cavae--> right atrium This route best describes the systemic circuit.

intrinsic conduction system of the heart

sets the basic rhythm of the beating heart

pacemaker potential (pacemaker cells)

slow depolarization due to both opening of Na+ channels and closing of K+ channels

hemocytoblast

stem cell at the center of hematopoiesis

blood flow through heart

superior vena cava--> right atrium--> tricuspid valve--> right ventricle--> pulmonary semilunar valve--> pulmonary trunk--> pulmonary arteries--> capillary beds of the lungs--> pulmonary veins--> left atrium--> bicuspid valve--> left ventricle--> aortic semilunar valve--> aorta--> systemic arteries--> superior and inferior vena cava

autoregulation

the ability of tissues to regulate their own blood supply

hemostasis

the body's way of stopping a break in a blood vessel wall

cardiac reserve

the difference between the rate at which the heart pumps blood and its maximum capacity for pumping blood at any given time

left atrium

the left upper chamber of the heart that receives oxygenated blood from the pulmonary veins

right atrium

the right upper chamber of the heart that receives deoxygenated blood from the venae cavae and coronary sinus

What are the functions of blood?

transport, protection and regulation

blood flow through vessels

Heart --> arteries --> arterioles --> capillaries --> venules -->veins --> heart

cardiac output equation

Heart Rate (HR) X Stroke Volume (SV)

differences between cardiac and skeletal muscle

Cardiac: one nucleus Skeletal: multiple nuclei Cardiac: cannot achieve tetanus Skeletal: can achieve tetanus Cardiac: gap junctions Skeletal: no gap junctions Cardiac: contracts together as a unit Skeletal: can contract independently Cardiac: intercalated discs Skeletal: no intercalated discs Cardiac: pacemaker cells Skeletal: no pacemaker cells Cardiac: almost completely reliant on aerobic respiration Skeletal: uses both aerobic and anaerobic respiration. Cardiac: Ca2+ from sarcoplasmic reticulum & extracellular fluid Skeletal: Ca2+ from the SR only.

pathway for erythropoiesis What organs, tissues, and hormones are involved?

Phase 1 - ribosome synthesis in early erythroblasts Phase 2 - hemoglobin accumulation in late erythroblasts and normoblasts Phase 3 - ejection of the nucleus from normoblasts and formation of reticulocytes

coagulation (last 2-3 steps)

Prothrombinase converts prothrombin to thrombin. Thrombin then converts fibrinogen into the fibrin mesh.