vascular smooth muscle/dysfunction/hypertension

Question 1

hypertension

Answer 1

• systolic exceeding 130 mmHg
• diastolic exceeding 80 mmHg

Question 2

why is hypertension a problem?

Answer 2

• early stage is ok
• major risk factor for dvlpmt of cardiovascular diseases (leading cause of death worldwide)
• chronic high blood pressure can lead to retinopathy, renal failure, peripheral vascular disease, hemorrhages/stroke/dementia

Question 3

main issue of hypertension

Answer 3

it is a risk factor for cardiovascular disease

Question 4

types of hypertension

Answer 4

• primary (essential)
• secondary

Question 5

primary/essential hypertension

Answer 5

• chronic high BP w/ no identifiable cause
• likely results from multiple interacting risk factors
• 90% of hypertension cases

Question 6

secondary hypertension

Answer 6

• high blood pressure caused by identifiable condition
• causes include: ****

Question 7

equation for hypertension

Answer 7

BP = CO x SVR
- CO = cardiac output: volume of blood pumped by heart per unit of time
- SVR = systemic vascular resistance: resistance to blood flow offered by all the systemic vasculature

Question 8

wht does the balance of CO and SVR depend on?

Answer 8

complex interactions btwn cardiovascular, neural, renal and endocrine systems

Question 9

resistance arteries

Answer 9

• most imp blood vessel to controlling BP
• regulate systemic blood pressure by influencing peripheral vascular resistance
• control capillary pressure and microvascular fluid exchange
• direct blood flow to tissues and organs based on metabolic demands
• contain thick layer of smooth muscle**? cells
• also contain layer of endothelial cells

Question 10

vasodilation vs vasoconstriction

Answer 10

• vasodilation: less resistance, increase blood flow
• vasoconstriction: more resistance, decrease blood flow

Question 11

intrinsic and extrinsic mechanisms

Answer 11

• intrinsic: ca2+ sensitization, membrane potential
• extrinsicL neurotransmitters, circulating hormones, endothelial factors, local factors form surrounding tissue

Question 12

how does smooth muscle contract?

Answer 12

• dense bodies —> anchored to plasma membrane — pull it in?
• thick filaments (myosin)
• thin filaments (actin)

Question 13

myosin

Answer 13

• filamentous
• swivel around sort of
• phosphorylation allows myosin to do something??
• ## like the motor

Question 14

why is calcium important to smooth muscle interaction?

Answer 14

• ## the kinase which phosphorylates myosin is calcium-dependent

Question 15

what mechanisms control vascular smooth muscle contraction?

Answer 15

• electromechanical coupling
• pharmacomechanical coupling
• Ca2+ sensitization
• endothelium-dependent relaxation

Question 16

membrane potential

Answer 16

• potassium often present in high concentrations on the inside of cells (at rest)
  -??*

Question 17

wht is membrane potential at any given time determined by?

Answer 17

• relative ion concentrations inside/outside the cells
• activity of elecrogenic pumps that maintain ion concentration gradients
• permeability of cell membrane to ions through specific ion channels

Question 18

depolarization vs hyperpolarization

Answer 18

• depolar: more positive vals
• hyperpolar: more negative vals

Question 19

which membrane potentials lead to relation/contraction

Answer 19

outward currents = hyper polarization = relaxation
inward currents = depolarization = contraction
dilators/constrictors must be able to move membrane potential to one side to cause relaxation/contraction

Question 20

calcium sensitization

Answer 20

• process by which force generation is maintained or increased w/o changes in cytosolic Ca2+ lvls
• achieved by inhibition of MLCP
• force generation can be maintained without sustained high levels of cytosolic Ca2+

Question 21

what’s a powerful way to regulate the contractile state of smooth muscle?

Answer 21

regulation of MLCP activity

Question 22

wht kind of protein is MLCP?

Answer 22

heterotrimeric protein

Question 23

three categories of treatments for hypertension

Answer 23

• reduce blood volume
• reduce systemic vascular resistance
• reduce cardiac output