Anatomy module 4.1 Flashcards by Amy Reid

Systole

phase of contraction–Depolarize

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Diastole

phase of relaxation–repolarize

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Atrial and ventricular Diastole (late diastole)

Both atria and ventricles are relaxed
Blood is flowing from the veins into Right Atrium and into the Left Atrium
The AV valves are open and the SL Valves are closed

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Atrial Systole

Initiated by depolarization
Preceded by the “P” wave of EKG
Atria contract
Blood flows from AV Valves to the Ventricles
Most Ventricular filling occurs before atrial systole

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What is the advantage of atrial systole?

Forces last amount of blood out of the atrium into the ventricle.

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Ventricular Systole (and atrial diastole)

Action potential has now traveled along the
Bundle of HIS to the ventricles.
It is preceded by the QRS wave of the EKG
The ventricles contract

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The _____ventricular pressure causes the ______to ____ and a moment later the SL valve to _____. The ____ of ____valves cause the _____heart sound
(still a part of Ventricular Systole ( and atrial systole)

Increased
AV Valves
Close
Open
Closing 
AV valves 
first

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The stage called _______occurse when the ______close but before the _____valves open.

Isovolumetric contraction
AV valves
SL Valves

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Muscle contraction stays same length

Isovolumetric contraction

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The stage called ______begings when _____valves _____.

Ventricular ejection
SL
Open

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Ventricular diastole

Ventricles relax

Preceded by the T wave of EKG

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Ventricular Diastole cont’d.

The _____ventricular pressure causes the SL valves to ____and a moment later the AV valves to____.

decreased
close
open

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The closure of the ____ valves causes the ____ heart sound

Second

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The stage called ______occurs when the ____valves close but before the _____valves open

isovolumetric relaxation
SL
AV

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Ventricular filling actually begins when the ____valves open

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Another cycle begins when the____fires another electrical signal

SA NODE

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The volume of blood ejected from each ventricle per minute

Cardiac output

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The number of contractions per minute

heart rate

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Volume of blood ejected by a ventricle per beat

Stroke Volume

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equation for CO, HR and SV

CO=SV*HR

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Frank Sterling Law

The more the heart muscle is stretched during diastole, the greater the force of contraction during systole

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Volume of blood returning to the right ventricle.

Venous Return

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Degree of stretch on the heart before it contracts

Pre-Load

increases stroke volume

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Forcefulness of contraction of individual ventricular muscle fibers

Contractility

increases stroke volume

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Pressure that must exceed before ejection of blood from the ventricles can occur. "downstream"

After-Load | Decreases stroke volume

Substances that either increase or decrease contractility

Inotropic effect

Measurement of the % of blood leaving your heart each time in contracts

Ejection Fraction | EF=SV/EDV * 100

Cardiac Control centers are located....

Medulla oblongata

``` Originate in the cardioinhibitory center post-ganglionic axons release the neurotransmitter acetylcholine decrease rate of firing of SA node Responsible for vagal tone vagus nerve cause decrease in cardiac output ```

Parasympathetic signals

Originate in the cardioacceleratory center post-ganglionic axons release the neurotransmitter norepinephrine increase rate of firing SA Node Increase contractility of cardiac muscle fibers positive inotropic effect

Sympathetic signals

3 layers of blood vessel walls

``` Tunica Intima (Interna) SIMPLE SQUAMOUS Tunica Media VASCULAR Tunica externa (adventitia) FIBROUS CONNECTIVE ```

``` Only layer of capillary walls Innermost layer in direct contact with lumen consists of simple squamous epithelium smooth layer; facilitates flow of blood also known as endothelium ```

Tunica Interna

Contains smooth muscle contains elastic connective tissue middle layer

Tunica Media

Consists of fibrous connective tissue | outermost layer

Tunica externa (adventitia)

Sequence of flow of 3 major types of blood vessels

1) ARTERIES---2) CAPILLARIES---3) VEINS---Back to the heart

Carries blood away from heart

Arteries

Allows exchange of substances between blood and body tissues

Capillaries

Carries blood back to the heart

Veins

Wall contains intercellular CLEFTS Wall consists of only simple squamous epithelial cells Site of exchange between plasma and interstitial fluid

Capillaries

Smallest artery contains greatest proportion of smooth muscle in its wall Capable of most significant vasoconstriction and vasodilation Major "resistance vessels"

Arterioles

Contains greatest proportion of elastic tissue in its wall High elasticity stretch and recoil of vessel wall maintains blood pressure; "Pressure Reservoir" Vessel with highest pressure Transports blood away from heart thickest-walled vessels

Artery

Contains valves thin walls are easily distended; "volume reservoir" for blood vessel with lowest pressure transports blood toward heart

Veins

Smallest vein

Venule

Volume of blood the flows through any tissue in a given time period

Blood flow

Hydrostatic pressure exerted by blood on walls of a blood vessel

Blood pressure

Driving force of blood flow that is generated by heart contraction. this is maintained by the stretch and recoil of the _____walls

pressure gradient | Artery

If blood pressure increases, blood flow_____

increases

Vessel type with the highest pressure is _____and the lowest pressure is _____

Artery | Vein

Blood vessels in order of highest to lowest blood pressure

``` Aorta Artery Arterioles Capillaries Venules Veins Vena Cavae ```

Blood flow is driven by the blood pressure gradient, but is opposed by ______.

Peripheral Resistance

Friction between walls and blood vessels and the blood | Opposition to blood flow through blood vessels

Peripheral Resistance

Highest pressure attained in arteries during systole

Systolic Blood Pressure

Lowest arterial pressure during diastole

Diastolic blood pressure

Average blood pressure in arteries

Mean arterial blood pressure

Difference between systolic and diastolic pressure

Pulse Pressure

Arterial blood pressure is commonly measured in the _____artery

Brachial

Alternate expansion and recoil of elastic arteries after each systole of the left ventricle creates a traveling pressure wave

Pulse

Pulse is characterized of what vessel type?

Elastic Artery

Pulse is a function of what type of tissue?

Elastic connective

As ______increases, blood flow _____

Peripheral Resistance | Decreases

What two factors contribute to P.R.?

Vascular Resistance --vessel diameter (as this increases resistance decreases) --vessel length (as this increases, resistance increases) Blood Viscosity

Which factor of P.R. is involved in the homeostatic regulation

``` Vessel Lumen (Diameter) Arterioles most significant ```

The widening of vessel diameter due to smooth muscle relaxation is known as:

Vasodilation

The narrowing of vessel diameter due to contraction of smooth muscle in its wall is called:

Vasoconstriction

EPINEPHERINE IS A

VASOCONSTRICTOR

Changes in arteriole diameter are important for 2 reasons:

Systemic Changes (ANS--Sympathetic, Endocrine system) Autoregulation

What specific division of the nervous system is primarily involved in regulation of arteriole diameter

Sympathetic Nervous System

Constant discharge by the Sympathetic Nervous System keeps arterioles slightly constricted under normal conditions. This is called:

Vasomotor Tone

Increased signals in the sympathetic NS lead to

Vasoconstriction

Decreased signals in the sympathetic NS lead to

Vasodilation

What are the hormones that influence arteriole diameter?

Epinepherine and Norepinephrine ADH Angiotnsion II Atrial Natriuretic Peptide (ANP)

What structural features of capillaries promote exchange between plasma and interstitial fluid?

Thin cell walls Intercellular cleft Fenstrations

What blood components cannot normally exit capillaries?

Red Blood Cells | Plasma Proteins

Movement of dissolved molecules in response to a concentration gradient

Diffusion | Many substances enter and leave capillaries by diffusion

Movement via pinocytotic vescicles is called

Transocystosis | Important for Large, lipid-insoluble molecules that can't cross capillary walls in any other way

Movement of water and small solutes in response to a pressure gradient is called

``` Bulk Flow (Important for regulation of relative volumes of blood and interstitial fluid.) ```

Pressure driven movement of fluid and solutes FROM blood capillaries INTO interstitial fluid

Filtration

Pressure driven movement from interstitial fluid INTO BLOOD capillaries

Reabsorption

_______pressure within capillary favors flow____the capillary

Blood Hydrostatic | Out of

_____(due to plasma proteins) within the capillary favors flow____the capillary

BCOP | Into

How is the slight excess flow of fluid out of the capillary returned to circulation?

Via lymph system

Volume of fluid and solutes reabsorbed normally is almost as large as the volume filtered. "near equilibrium"

Starlilng's Law of the Capillaries

What would happen if.... | Lower than normal concentration of normal plasma proteins, due perhaps to liver dysfunction

Lower blood osmotic pressure (BCOP)

What would happen if... | Increased capillary pressure due to poor venous return

Increased blood pressure | Causes more fluid to be filtered out of capillaries

What would happen if.... | Blockage of lymphatic circulation

Lymphadema

Abnormal increase in interstitial fluid volume. Lack of proteins

Edema

What structures prevent backflow of blood within most veins?

Valves

Formula for relationship between mean arterial pressure, cardiac output, and peripheral resistance

CO=MAP/R; MAP=CO x R

If peripheral resistance and/or CO_____blood pressure will increase

INCREASE

Arterial blood pressure can be homeostatically regulated by regulating either _____or ______

CO | Resistance

Homeostatic regulation of arterial pressure is accomplished through the ______ reflex

Barorecptor | short term regulation

Receptors for Baroreceptor reflex are located in the walls of the _____and _____ and detect _______. When blood pressure increases, the receptors are______and send____impulses

``` Arch of aorta Coratid sinus pressure changes stretched/stimulated more ```

The integration center for the baroreceptor reflex is the_____in the _____

Cardiovascular | Medulla

The efferent pathway for the baroreceptor reflex is along_____and ______neurons

Parasympathetic | Sympathetic

The effectors for the baraorecceptor reflex are the _____and ______

Myocardium | smooth muscle

Detects changes in blood level of O2, CO2 and H+

Chemoreceptors

Regulates blood pressure

Baroreceptors

All arteries of systemic circulation are branches of the ____.

Aorta

All veins of systemic circulation are tributaries of the _____or the ____

Superior Vena Cava | Coronary Sinus

Anatomy module 4.1 Flashcards

(99 cards)