deck_16348459 Flashcards
Diffusion
Passive movement high to low concentration
Transcytosis
Active transport of larger fat insoluble
Filtration
Movement of water higher to lower concentration
Diffusion occurs rapidly when?
short distance, large concentration gradient, small ions/molecules
Diffusion is important for?
solute exchange
How transcytosis works?
*
* Hormone enters one side of cell via pinocytic vesicle and exits other side
What is Bulk flow?
large numbers of ions, molecules, moving in same direction passively
Bulk Flow Filtration movement occurs where?
capillaries to interstitial fluid
Bulk Flow Re-absorption occurs where?
Interstitial fluid to capillaries
Filtration: Blood Hydrostatic Pressure
Pressure of blood on vessel walls pushes molecules out
Filtration: Interstitial Fluid colloid osmotic pressure
Interstitial fluid pulling from capillaries to IF
Re-absorption: Blood Colloid osmotic pressure
Albumins pull fluid from IF into blood
Re-absorption: Interstitial fluid Hydrostatic pressure
Pressure pushes fluid from IF to capillaries
Movement across capillary is largely dependent on?
Hydrostatic and osmotic pressure of blood
What is Net Filtration Pressure
Balance of pressures determining direction of fluid flow
What is edema?
Swelling - abnormal IF volume
What are hemodynamics
Factors affecting blood flow
Blood flow is dependent on which two factors?
Pressure Difference
Peripheral Resistance
Systolic Blood Pressure
Highest pressure attained in arteries during systolic contraction
Diastolic Blood Pressure
Lowest pressure attained in arteries during diastolic relaxation
Mean arterial pressure
average BP in arteries
Which is higher Arterial or Venous pressure?
Arterial
Capillary pressure is lower than artery because?
Increased surface area and blood spreading
Blood pressure in veins maintained by what two things?
Valves
muscular compression of veins
Capillary blood flow is slow and allows time for?
Time for capillary exchange
What is Venous Return
Amount of blood to right atrium per min
Where is highest pressure located
Aorta - pressure keeps decreasing from there
Peripheral Resistance is dependent on what 3 factors?
Size of lumen in vessel
Blood vessel length
Blood viscosity
How does size of lumen affect fluid movement
Smaller lumen, more resistance
Larger lumen, less resistance
How does blood vessel length affect fluid movement?
Longer the vessel, more resistance
How blood viscosity affects fluid movement
Increased solutes, etc.. increase viscosity = increase resistance
What is Systemic Vascular Resistance aka. Total Peripheral Resistance
Total resistance entire vascular system
What contributes most to Systemic Vascular Resistance
Arterioles (most), capillaries, venules,
Why do arterioles contribute the most to Systemic Vascular Resistance
The ability to contract because of more smooth muscle
Velocity of blood flow is relationship between what?
Fluid velocity with cross sectional area of closed tube
What has the most cross sectional area, therefore slowest blood velocity?
Capillaries and venules
What are the two regulatory pathways for Homeostatic mechanisms
Autoregulation
Central regulation
How does autoregulation work
Opening or closing pre-capillary sphincters to regulate BP
What factors lead to autoregulation
Vasodilating and constricting chemicals (endothelins)
Changes in oxygen levels
If there is low blood in pulmonary tissues why would vessels constrict?
No oxygen to oxygenate blood
What does central regulation involve?
Neural and endocrine mechanisms
Which neural mechanisms affect BP
Cardioacceleratory/inhibitory centers
How does endocrine system affect BP
Releasing vasoconstrictors
What 4 mechanisms do Central regulation mechanisms receive input from?
Baroceptors
Chemoreceptors
Proprioceptors
Limbic system & higher brain centers
Baroreceptors are located in walls of ?
Carotid sinuses - brain pressure
Aortic sinuses - systemic pressure
Right atrium
What do cardiac accelerator nerves do?
Increase HR and cardiac output
What do Vagus nerves do?
parasympathetic nervous system decrease HR and CO
What do Vasomotor nerves do?
cause vasoconstriction of blood vessels
What do endocrine responses use for BP and flow?
Hormones that provide short term and long term regulation using functions of heart, kidneys, pituitary
Immediate Hormonal response to low blood pressure and volume?
Immediate response:
Adrenals release epinephrine and norepinephrine
What is the Renin – Angiotensin –Aldosterone system
Hormonal Regulation BP
Cascade:
Kidneys release renin
Renin converts angiotensin into angiotensin II (AG II)
AG II increases BP
What is the goal of Anti-diuretic Hormone (ADH) aka “vasopressin”
Increase BP by kidneys absorbing more H20 (less pee)
What is the goal of Atrial Natriuretic Peptide (ANP)?
Protein released from heart to decrease BP — more pee
What is syncope? fainting
Lack of blood flow to brain sudden loss of consciousness
What is shock
cardiovascular crisis - low BP, peripheral blood flow
Hypovolemic Shock –
- decreased total volume of blood (ie.
hemorrhaging or excessive dehydration)
- decreased total volume of blood (ie.
Cardiogenic Shock –
poor/lack of normal heart functioning (MI,
arrythmias, fibrillations)
Obstructive Shock –
blockage of blood flow (thrombus & embolus
formations)
Anaphylactic Shock –
massive vasodilation in response to an allergen
Neurogenic Shock –
damage to nervous system interrupts normal neural
BP regulation
Septic Shock –
shock in response to sepsis
Signs and Symptoms of Shock
Drop in BP
Decreased blood to organs
Pulse
traveling pressure wave generated by systole & diastole of the ventricles.
Korotkoff sounds
sounds heard through the stethoscope
Systolic Blood Pressure (SBP)
HIGHEST pressure attained in arteries during
systolic contraction
Diastolic Blood Pressure
LOWEST pressure attained in arteries during
diastolic relaxation
Pulse pressure
is the difference between systolic & diastolic pressures
Hypertension
increase in the pulse pressures beyond the normal range
Hypotension
decrease in the pulse pressures beyond the normal range
Vasculitis
inflammation of the vessel wall, due to autoimmune disease or infection
Phlebitis and arteritis
Phlebitis = inflammation of a vein
arteritis = inflammation of an artery
Temporal arteritis
Inflammation of the temporal artery in the scalp
Atherosclerosis
the formation of lipid lumps (atheromas) in the blood vessel wall
m/c cardiovascular disease
Coronary artery disease
Atherosclerosis with narrowing of the arteries supplying blood to the heart
muscle
more likely heart attack
Carotid artery disease
Atherosclerosis with narrowing of one or both of the carotid arteries in the neck.
more likely stroke
Peripheral artery disease
- Atherosclerosis that causes narrowing of the arteries
in the legs or groin.
Chronic Venous Insufficiency
damages veins causing blood to pool in your legs.
Arterial thrombosis
blood clot that develops in an artery.