Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Phys > Week 4 - Cardiovascular 2 > Flashcards

Week 4 - Cardiovascular 2 Flashcards

1
Q

Cardiac output

A
  • amount of blood pumped out by each ventricle in 1 min
  • calculation: HEART RATE & STROKE VOL
  • affected by autonomic activity, hormones & temp
  • CARDIAC RESERVE: diff vetween max & resting CO, inc. w/ fitness, dec. with disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Heartrate - regulation factors

A
  • Pacemaker cells
  • Neural control from ANS
    → Sympathetic inc. HR
    → Parasympathetic dec. HR
  • hormones
  • conc. of ions in blood (Na+, K+, Ca2+)
  • age
  • gender
  • physical fitness levels
  • temp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cardiac output - stroke volume

A

STROKE VOL = END DIASTOLIC VOL - END SYSTOLIC VOL

EDV: max blood collected in ventricles at end of diastole
influenced by: Filling time
- VENOUS RETURN: amount of venous blood returned to heart
- PRELOAD: pressure on cardiac wall due to blood vol

ESV: blood in ventricle at end of systole
influenced by: CONTRACTILITY: symp. stimulation inc. contractility, drugs reduce this
- AFTERLOAD : force ventricles produced to open valves, reject blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

preload

A

Length or degree of stretch of sarcomeres in ventricular cells before contract

FRANK STARLING LAW: inc ventricular muscles stretch, leads to more forceful contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

afterload

A

Force that right & left ventricles must OVERCOME in order to EJECT blood into their respective arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

contractility

A

hearts intrinsic pump ability to GENERATE TENSION

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

cardiac contractility - regulation

A
  • HORMONAL CONTROL
  • hormones (thyroid or norepinephrine) can beta-adrenergic receptors in cardiac cells, opening Ca2+ CHANNELS
  • opening of Ca2+ channels inc. length of plateau phase of ventricular depolarisation, prolonging ventricular contraction
    SNS: sympathetic nerve fibres release norepinephrine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

cardiac output- effect of exercise

A
  • PROPRIOCEPTORS: HR inc. at beginning bc. signals from joints & muscles
  • VENOUS RETURN: muscular activity inc. venous return causes inc SV
  • inc HR & inc SV cause inc. CO
  • sustained exercise programs produce VENTRICULAR HYPERTROPHY
  • inc SV allows heart to beat more slowly at rest
    inc. cardiac reserve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

veins

A

LARGE: inc superior & inferior vena cava contain 3 vessel wall layers; slender tunica media: ELASTIC & COLLAGEN FIBRES

MEDIUM: 2-9mm (diametre) - thin tunica media - SMOOTH MUSCLE CELLS & COLLAGEN FIBRES. tunica externa - THICKEST: SMOOTH MUSCLE CELLS & LONGITUDINAL BUNDLES OF ELASTIC COLLAGEN FIBRES

VENULES: collect blood from capillary beds- smaller than 50 micrometres → lack tunica media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

arteries

A

ELASTIC: inc. pulmonary trunk & aorta - resilient, capable of STRETCHING & RECOILING as heart beats & arterial pressure changes

MUSCULAR: distribute blood to body’s skeletal muscles & internal organs

ARTERIOLES: poorly defined tunica externa, one or two layers of smooth muscle cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

capillaries

A
  • SMALLEST BLOOD VESSEL
  • deliver blood to TISSUES & CELLS
  • lumen big enough for a single erythrocyte to pass
  • most tissues have a rich capillary supply )except tendons, ligaments & cartilage)
  • Function: EXCHANGE 02, CO2 NUTRIENTS, HORMONES BETWEEN BLOOD & INTERSTITIAL FLUID
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Capillaries (types) - Continuous

A
  • occur in most tissues

- endothelial cells have tight junctions w/ intercellular clefts (allow water & small solutes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Capillaries (types) - Fenestrated

A
  • kidneys, small intestines, hypothalamus
  • organs that require rapid absorption or filtration
  • filtration pores; allow passage of molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Capillaries (types) - Sinusoids

A
  • liver, bone marrow, spleen, endocrine organs
  • irregular blood-filled spaces; some have large fenestrations
  • allow proteins & blood cells to enter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

venous system

A
  • low pressure (~10% press. in ascending aorta)
  • contain valves to prevent back flow of blood →defects cause varicose veins/hemorrhoids
  • 64% of total blood volume in venous system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

venous return

A
    • gravity helps drain blood form head & neck of skeletal & thoracic pumps help w/ venous return from lower body
  • SKELETAL MUSCLE PUMP: in the limbs contraction of muslce exerts pressure on veins & valves direct blood towards the heart; no back flow
  • THORACIC RESPIRATORY PUMP: works through dec. thoracic pressure during inhalation draws blood into thoracic veins & right atrium
  • improved by exercise
17
Q

capillaries - exchange

A
  • water, small molecules, ions: cross capillary walls adjacent endothelial cells or fenestrated pores
  • other ions (Na+, K+, Ca2+): cross walls through chanells
  • large water soluble compounds: cannot cross wall except in fenestrated capillaries
  • lipids, respiratory gases: can diffuse through endothelial cells
  • plasma protein: cannot cross walls except at sinusoids of liver
18
Q

Capillary exchange - filtration

A
  • selective movement of material in instertitial fluid through capillary walls → act as a filter, directed OUTWARDS
  • promoted by BLOOD HYDROSTATIC PRESSURE
19
Q

Capillary exchange - reabsorption

A
  • movement of material from instertitial fluid into capillaries - directed INWARDS
  • promoted by BLOOD COLLOID OSMOTIC PRESSURE
20
Q

Circulation - blood flow

A
  • measure in ml/min. amount of blood flow through an area in given time, blood flow through entire vascular sys = cardiac output & fairy constant while blood flow through specific organs vary
21
Q

Circulation - blood pressure

A
  • measured in MMHG → force per unit area the blood exerts on a vessel wall
  • refers to systemic arterial BP in largest arteries near heart
  • diff in BP (BP Gradient) is driving force that keeps blood moving
22
Q

peripheral resistance

A

refers to opposition to blood flow & is measure of friction encountered by blood on its passage through vessels

  • VISCOSITY: thickness of fluid due to formed elements in blood, constant unless disease
  • VESSEL LENGTH: inc. length increases resistance → constant
  • VESSEL DIAMETRE: smaller diametre = inc resistance varies inversely W/ THE FOURTH POWER OF VESSEL RADIUS. turbulences inc resistance
23
Q

blood pressure - arterial

A
  • force that blood exerts against a vessel wall measured at brachial artery of arm
  • SYSTOLIC PRESS: BP during ventricuar systole
  • DIASTOLIC PRESS: BP during ventricular diastole
  • NORMAL - young adult: 120/80 mmHg

PULSE PRESSURE: systolic -diastolic → stress exerted on small arteries
MEANARTERIAL PRESSURE: measurements taken at intervals of cardiac cycle. diastolic presss + (1/3 pulse press)

24
Q

blood pressure - systemic

A
  • pumping of heart generates blood flow
  • pressure arises from resistance
  • systemic BP is highest in aorta & declines until it reaches O at the right atrium
  • most pronounced change in BP occurs in arterioles
25
Q

blood pressure - abnormal

A

HYPERTENSION:

  • chronic resting BP > 140/90
  • consequences → can weaken small arteries & cause aneurysms

HYPOTENSION:

  • chronic low resting BP 90/60 - only diagnosed if symptoms are present
  • fatigue, dizziness, light headedness, nausea
  • caused by blood loss, dehydration, anemia
26
Q

baroreceptor reflex

A

Changes in BP detected by stretch receptors in large arteries above heart:

  • aortic arch
  • aortic sinuses (behind aortic valves cusps)
  • carotid sinus ( base of each internal carotid artery

Autonomic negative feedback response

  • baroreceptors send constant signals to blood stem
  • inc. BP signals rise, inhibits vasomotor centre, dec. vasodilation, deb BP
  • dec. BP, signals rate drop, excited vasomotorcentre inc vasoconstriction, inc BP
27
Q

chemoreceptor reflex

A

Chemoreceptors in aortic bodies & carotidblood →in aortic arch, subclavian arteries, external carotid arteries

Autonomic response to changes in blood chemistry

  • pH, O2, CO2
  • primary role: adjust respiration
  • secondary role: vasomotion → hypoxemia, hypercapnia & acidosis stimulate gas exchange + chemoreceptors instruct vasomotor centre to cause vasoconstriction ,inc BP, inc. lung perfusion
28
Q

hormone regulation

A

ANGIOTENSIN II: potent vasoconstrictor , raise BP
ALDOSTERONE: promote Na+ & water retention by kidneys, inc. blood vol & BP
ATRIAL NATRIURETIC PEPTIDE (ANP): inc urinary Na+ excretion reduces blood vol, lowers BP
ANTI-DIURETIC HORMONE (ADH): promote water retention & raises BP
EPINEPHRINE & NOREPINEPHRINE: exert effects on most blood vessels by binding - basocontriction & inc BP in skeletal & cardiac: cause vasodilation

29
Q

lymphatic system

A

Vessels: transport fluid (lymph) back to the blood that has escaped from vascular system

Tissues & organs: house phagocytic cells & lymphocytes which are important for immune defence system

30
Q

lymphatic system - functions

A

FLUID RECOVERY: 15% of fluif that is not reabsorbed by blood capillaries would amount to 2-4 L of water/da and 1/4-1/2 of plasma proteins →circulatory failure

IMMUNITY: also picks up foreign substances from the body, passes through lymph nodes where immune cells await

LIPID ABSORPTION: in small intestine special lymphatic vessels absorb dietary lipids which are not absorbed by blood vessels

31
Q

lymphatic capillaries

A
  • slightly larger in diametre than blood capillaries closed at one end
  • found all around the body except CNS, bone & vascular tissues
  • collect & transport a portion of interstitial fluid (lymph) together w/ bacteria (in case of infection), cellular debris & any leukocytes
  • interstitial fluid in extracellular space is formed from blood through the process of filtration in capillaries
32
Q

lymph flow

A
  • lymph flows at low pressure & speed
  • moved along by rhythmic contractions of lymphatic vessels: stretching of vessels stimulates contraction
  • flow aided by skeletal muscle pump
  • thoracic pump aids flow from abdominal to thoracic cav.
  • valves prevent backflow
  • rapidly flowing blood in subclavian veins, draws lymp into it
  • exercise significantly inc. lymphatic return

Phys (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions