- Laterally by the lungs - Anterior to the vertebral column - Posterior to the sternum - Rests on the diaphragm inferiorly

Cardiovascular Physiology Flashcards by Chloe Rivas

Cardiovascular system is responsible for

Transportation
- oxygen and nutrient supply
- get rid of carbon dioxide

Regulation
- regulatory hormones from endocrine glands
- regulation of body temperature

Protection
- against injury and foreign microbes or toxins

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Protection:
-protects against injury and foreign microbes or toxins introduced into the body EXAMPLE

platelets- blood clotting; WBCs

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What are the two types of Circulatory System

Open circulatory system
Closed circulatory system

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Simple animals consisting of a single cell layer do not have a circulatory system, instead, gases, nutrients, and waste are exchanged by

diffusion

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Advantage of closed system

More effective in transporting circulatory fluids to meet the high metabolic demands of the tissues and
cells of larger and more active animals

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What are the three basic components of the
Cardiovascular System and function

Heart- as a pumping organ of the system

Blood vessels- as containers, through which the circulation occurs

Blood- as transport medium of the circulation

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The heart:
- Shape
- Weighs
- Location

Cone-shaped
between 250 to 350 grams
in the center of the chest in an area called the MEDIASTINUM

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Heart is bordered by

Laterally by the lungs
Anterior to the vertebral column
Posterior to the sternum
Rests on the diaphragm inferiorly

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The heart:
- Slightly left of the ___
- Extends from the level of the ___ rib to about the level of the ____ rib
- ____ (PMI) - where the heartbeat sounds or murmurs are heard most prominently or distinctly.

midline
2nd, 6th
Point of maximal intensity

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(Coverings of the Heart)
Protects the heart
Anchors it to the surrounding structure
Prevents overfilling of the heart with blood

Fibrous pericardium

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Covering of the heart- thin slippery serous membrane

Serous Pericardium

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Coverings and Layers of the heart

Parietal Pericardium
- Fibrous
- Serous
- Pericardial cavity
Myocardiuum (middle and thickest)
Endocaridum (innermost layer)

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inflammation of the pericardium
the specific clinical finding characterized by scratching or grating sound

Pericarditis
Pericardial friction rub

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is pressure on the heart that occurs when blood or fluid builds up in the space between the heart muscle and the outer covering sac (pericardium) of the heart.

Cardiac tamponade

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First chamber: Right Atrium function

Receives and collects oxygen-poor blood from the body through the superior and inferior vena cava and then pumps the blood into the right ventricle through the tricuspid valve.

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Second chamber: Right Ventricle function

Receives deoxygenated blood from the right atrium, pumps it thru the pulmonary valve into the pulmonary artery, sending the blood to the lungs for oxygenation

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Third chamber: Left Atrium function

Receives oxygenated blood from the lungs through the pulmonary veins. Then pumps this oxygen-rich blood through the mitral valve into the left ventricle

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Fourth chamber: Left Ventricle

Receives oxygenated blood from the left atrium and pumps it through the aortic valve into the aorta, delivering oxygenated blood to the rest of the body.

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The heart valves

Atrioventricular Valves:
- Bicuspid/Mitral
- Tricuspid

Semi-lunar Valves:
- Aortic
-Pulmonary

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Operation of AV Valves:
1. Blood returning to the atria puts pressure against _____; then those are forced ____
2. As the ventricles fill, _____ hang limply into ventricles.
3. Atria contract, forcing additional blood into ____. AV valves open; atrial pressure is ___ than ventricular pressure
4. Ventricles ____, forcing blood against AV valve flaps.
5. AV valves ___
6. ____ tighten, preventing valve flaps from everting into atria. AV valves closed; atrial pressure less than ventricular pressure.

AV valves, open
AV valve flaps
ventricles, greater
contract
close
Chordae tendineae

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Operation of the SL valves

As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open.
As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the leaflets of semilunar valves and forcing them to close.

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Two types of valve problems (both decrease movement of blood)
1. - the valve shuts, but cannot open all the way
- thus decrease blood flow through the heart

- the valve opens, but cannot shut completely
  - thus, blood regurgitates backward through the heart

Stenotic (constricted) valve
Insufficient/Incompetent valve

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Abnormal aortic valve fails to ___, allowing blood to leak ____

close; backward

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abnormal sound caused by turbulent blood flow through a stenotic and insufficient valve

what is the treatment?

heart murmurs
Treatment:
- replace the defective valve with an artificial valve

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PATTERNS OF CIRCULATION 1. the movement of blood from the heart to the lungs and back to the heart again 2. supplies nourishment to all of the other tissues located throughout your body 3. supplies blood to the heart

1. Pulmonary Circulation 2. Systemic Circulation 3. Coronary circulation

In Systemic Circulation, 1. ______ - supplies blood to the kidneys. 2. ______- where it is passed through the liver and the sugars are filtered stored for use later.

Renal circulation Hepatic portal circulation

Anatomical differences in the right and left ventricle

Left ventricle: thicker walls, more thick when contracted, cavity is circular Right ventricle: thin walls, cavity is flattened into crescent-shaped and wraps around the left ventricle.

Summarizes the pathway that blood takes as it flows into, through, and out of the heart

Superior & Inferior Vena Cava Right Atrium Tricuspid Valve Right Ventricle Pulmonary Valve Lungs Pulmonary Veins Left Atrium Mitral Valve Left Ventricle Aortic Valve Aorta

Banding pattern of cardiac fibers 1. T tubules: 2. SR is: 3. Lacks- 4. Is there a Triad? 5. Thus system for delivering ____ is less elaborate in cardiac cell

1. Wider and fewer' 2. Less developed 3. Terminal cisternae 4. No 5. Calcium

Differences between skeletal and cardiac muscle: 1. All-or-none response

Skeletal: applies to contractile activity at the cellular level Cardiac: applies to organ level

Differences between skeletal and cardiac muscle: Means of stimulation

- Skeletal: stimulated to contract by nerve endings - Cardiac: self-excitable and can initiate their own depolarization

Cardiac muscles are self-excitable and can initiate their own depolarization - rest of the heart is spontaneous and rhythmic way: ___

- automaticity or autorhythmicity

Length of the refractory period in cardiac vs. skeletal

Cardiac: last 250 ms (prevents tetanic contractions which would stop the heart’s pumping action) skeletal: 1-2ms

refers to a specialized arrangement of cardiac muscle cells in the heart that allows coordinated and synchronized contraction of the heart muscle. The heart muscle, also known as ____, is made up of individual cardiac muscle cells called ____.

Functional syncytium: myocardium cardiomyocytes.

Functional syncytium: Cardiac muscle cells are interconnected by specialized structures called _____. These discs contain _____, which are channels that allow ions to pass between adjacent cells. This direct electrical connection enables rapid transmission of electrical impulses from one cell to another.

intercalated discs gap junctions

The bulk of the heart muscle is composed of_______ responsible for the pumping activity of the heart

contractile muscle fibers

1% of the cardiac muscles are ______ with the special ability to depolarize spontaneously

autorhythmic (self-rhythm)

The ability of the cardiac muscle to depolarize and contract is intrinsic Reasons:

1. presence of Gap Junctions 2. Intrinsic Cardiac Conduction system (consists of noncontractile cardiac cells specialized to initiate and distribute impulses throughout the heart)

- initiate action potentials - spontaneous electrical fluctuations in the heart. These cells are capable of generating rhythmic, repetitive action potentials without requiring external stimulation.

Pacemaker potentials

The sequence of events for pacemaker action potential: 1. Spontaneous flow of ions mainly through slow ____ slowly depolarizes TMP above____. This is called the _____ (also known as pacemaker current); it is active at TMPs of less than ____

Na+ channels, −60 mV funny current; −55 mV

The sequence of events for pacemaker action potential: 2. At TMP −55 mV, ____ channels open and continue slow ____

T-type Ca2+ depolarization

The sequence of events for pacemaker action potential: 3. _____ is the threshold potential for pacemaker cells.____ channels open and depolarize cell to___, then overshoot to ___

TMP −40 mV L-type Ca2+ 0 mV, +40 mV

The sequence of events for pacemaker action potential: 4. Delayed rectifier K+ channels counteract the L-type Ca2+ channels for a brief plateau phase and then return the TMP back to ___ as Ca2+ channels close.

−60 mV

A. The pacemaker potential gradually becomes ___ until it reaches ____, triggering an ____

less negative, threshold, action potential

Sequence of electrical events in contractile cells (Graph)

Depolarization Brief repolarization Plateau Repolarization

represents the process by which an electrical action potential leads to contraction of cardiac muscle cells. This is achieved by converting a chemical signal into mechanical energy via the action of contractile proteins

Excitation-contraction coupling

is the crucial mediator that couples electrical excitation to physical contraction by cycling in and out of the myocyte’s cytosol during each action potential

Calcium

Main contractile elements: ____ thick filaments with globular heads evenly spaced along their length; contains myosin ATPase. _____smaller molecule (thin filaments) consisting of two strands arranged as an alpha-helix, woven between myosin filaments

Myosin Actin

Regulatory elements: 1. double helix that lies in the groove between actin filaments. It prevents contraction in the resting state by inhibiting the interaction between myosin heads and actin. 2. complex with three subunits that sits at regular intervals along the actin strands. 3. ties troponin complex to actin and tropomyosin molecules. 4. inhibits activity of ATPase in actin-myosin interaction. 5. binds calcium ions that regulate contractile proc

1. Tropomyosin 2. Troponin 3. Troponin T (TnT) 4. Troponin I (TnI) 5. Troponin C (TnC)

CALCIUM-INDUCED CALCIUM RELEASE After a depolarization via sodium channels, calcium enters the ____ via _____, Calcium then activates ________ on the sarcoplasmic reticulum (SR. This special receptor senses intracellular calcium and triggers calcium release from the SR to further increase calcium availability in the cell. As the contraction ends, intracellular calcium returns to the SR via the SERCA calcium channel (grey).

cardiomyocyte, L-type calcium channels ryanodine receptors

The heart ____and ___ in a rhythmic cycle

contracts, relaxes

one complete sequence of pumping and filling

Cardiac cycle

THE HEARTBEAT (CARDIAC CYCLE

A. Cardiac diastole B. Atrial systole (ventricular diastole) C. Ventricular systole (atrial diastole)

Average, Normal Intracardiac and Vascular Pressures (mmHg)

Right atrium (0-4) Right Ventricle (25 sys/4 dias) Pulmonary Artery (25 sys/10 dias) Left Atrium (8-10) Left Ventricle (120 sys/10 dias) Aorta (120 sys/80 dias)

Divisions of the cardiac cycle

A. Systole- contracts (pumps blood out of the chambers into the arteries) B. Diastole- relaxation (refill of blood)

Systole Division (Valves: open or close)

1. Isovolumetric ventricular contraction - ventricles begin to contract but haven't generated enough pressure to open the aortic and pulmonary valves yet - AV Valves: closed - Aortic & Pulmonary Valves: closed 2. Ventricular ejection - the phase in which blood is forcefully ejected from the ventricles into the pulmonary artery and aorta. - AV Valves: closed - Aortic & Pulmonary Valves: open

Diastole Division (Valves: open or close)

Isovolumetric Ventricular Relaxation: - the early part of ventricular diastole. - AV Valves: closed - Aortic & Pulmonary Valves: close Ventricular Filling - phase in which blood flows from the atria into the ventricles. (atrial systole- increase pressure in the atria) - - AV Valves: open - Aortic & Pulmonary Valves: close

TWO Important Points: 1. Blood flow through the heart is controlled entirely by ____ 2. Blood flow along a pressure gradient, always _____ pressure through any available opening

pressure changes higher to lower

Heart Sounds: 1. The ____ creates the heart sound each heart beat 2. lub-dub,pause,lub-dub, pause (_____) 3. Lub- the first heart sound due to ____ (onset of systole) 4. Dub- the second sound against the closed ____

cardiac cycle quiescent period closed AV valves SL valves

are abnormal sounds heard during the cardiac cycle

heart murmurs

- is the process of producing an electrocardiogram, a recording of the heart's electrical activity through repeated

Electrocardiograph

Deflection waves:

- P wave (Atrial depolarization) - QRS complex (Ventricular depolarization) - T wave (Ventricular Repolarization)

The Intrinsic Cardiac Conduction System

1. Sinoatrial node (Pacemaker) 2. Atrioventricular node 3. Bundle of His/Atrioventricular bundle 4. Bundle branches 5. Purkinje fibers

The Control of heart rhythm

1. Pacemaker generates wave of signals to contract 2. Signals are delayed at AV node 3. Signals pass to heart apex 4. Signals spread throughout ventricles

amount of blood pumped from the left ventricle each minute

Cardiac output (mL/min)

Cardiac output is determined by _____ and_____

heart rate & stroke volume

To calculate cardiac output

Cardiac Output = HR × SV (HR= heart rate, SV=Stroke Volume)

It is the number of contractions/minute (beats per minute)

Heart Rate

It is the volume of blood pumped out of ventricle per contraction

Stroke volume

Cardiac output is precisely adjusted to meet needs of ____

tissues