PRIN 11 ANS Flashcards
(99 cards)
1
Q
What contributes to Hydrostatic Pressure?
A
(1) Viscous Resistance
(2) Gravity
2
Q
What is Pulse Pressure?
A
PP = SP - DP
3
Q
What is Mean Arterial Pressure?
A
MAP is the average arterial pressure during the cardiac cycle
4
Q
How can MAP be approximated?
A
Mean Arterial Pressure
MAP = DP + (PP/3)
5
Q
What are the two baro-receptors?
stretch receptors
A
Carotid Body
(located at bifurcation of carotid artery)
Aortic Baroreceptors
(located on Aortic Arch)
6
Q
How are the baro-receptors innervated?
A
carotid sinus - CNIX
aortic arch - CNX
Mix of both myelin & non-myelinated fibres
MO: nucleus tractus solitarius (NTS)
7
Q
Do veins contain some smooth muscle?
A
YES!
8
Q
Neurotransmitter Pathway
A
TYROSINE (via Hydroxylation) DOPA (via decarboxylation) DOPAMINE (Hydroxylation) NE (via methylation) E
9
Q
MAO
A
Mono-amine Oxidase
Converts Dopamine to NE
Therefore, a MAO inhibitor would allow for more Dopamine (used as anti-depressant)
10
Q
What controls the blood vessels?
A
Sympathetic ONLY. There is NO parasympathetic innervation of blood vessels
Parasympathetic simply exerts its effects by INHIBITING the sympathetic system (although there is always some Sympathetic Tone)
11
Q
What do the Baroreceptors actually detect?
A
Baroreceptors are sensitive to the RATE OF CHANGE of pressure, rather than absolute pressure
12
Q
a1
What is the effect?
A
NE...IP3/Ca2+ Constriction of Smooth Muscles *piloerectors *spincters: bladder & GI *uterus contractions eye
13
Q
a2
What is the effect?
A
E…Inhibits cAMP
(inhibits SNS)
pre-synaptic terminals (autoreceptors)
relax the smooth muscle in the walls … decreases GI motility
14
Q
B1
What is the effect?
A
E…Stimulates cAMP
Increases Cardiac Output & Heart Rate (SA Node)
Kidney: release renin to conserve water
15
Q
B2
What is the effect?
A
E …. Stimulates cAMP
Relaxation of Smooth Muscles and liberation of energy
Dilate Bronchioles
Dilate vessels in Muscles
Relax Uterus
Relax GI (no peristalsis)
Relax Bladder
Relax ciliary muscle … cycloplegia (loss of visual accomadation)
Stimulate Liver to perform glucogenolysis: LIBERATION OF ENERGY
16
Q
B3
What is the effect?
A
Stimulates cAMP
Fat Cells
17
Q
Sympathetic vs Parasympathetic
Where are the ganglia located?
A
Sympathetic: Ganglia located in sympathetic chain, far away from organs
Parasympathetic: Ganglia are located close to the organs they innervate
18
Q
Where are Muscarinic & Nicotinic Receptors located?
A
M receptors are on ORGANS which receive paraympathetic innervation
N receptors are in ANS ganglia and also in NMJ
19
Q
What is the function of Muscarinic receptors?
A
FUNCTION: to oppose most SNS actions at the level of the organs
20
Q
What is the distribution of Muscarinic receptors?
A
Constrict Bronchioles Decrease HR Relax GI (rest & digest) Relax Bladder Increased salivation Uterus Contractions Contract Circular muscle of Iris ... pupil constriction Contract Ciliary Muscle ... accomadation of near vision
21
Q
Sex Glands
A
Arousal: PNS
Orgasm: SNS
22
Q
What do sweat glands use?
A
Innervated by SNS but use M receptors via Ach
23
Q
Term for agonist to increase stimulation of a & B receptors
A
Sympatho-mimetic
Increase SNS
24
Q
Term for agonist to decrease stimulation of a & B receptors
A
Sympatho-lytic
Decrease SNS
25
Term for agonist to increase stimulation of M receptors
Vago-tonic
| ```
Increase PNS
note: Vago = CNX
```
26
Term for agonist to decrease stimulation of M receptors
Vago-lytic
| ```
Decrease PNS
note: Vago = CNX
```
27
What are the THREE fates of Ach?
(1) Broken down by AChE
(2) Re-uptake
(3) Diffusion & metabolized
28
What are the THREE ways to manipulate the PNS?
(1) M Agonist: (inc. PNS)
PILOCARPINE
(2) M Antagonist (dec. PNS)
ATROPINE
(3) AChE Inhibitor (inc. PNS)
NEOSTIGMINE
29
What are the main uses for AChE inhibitors?
| aka. Anti-cholinesterases
(1) Treat Myasethenia Gravis
| (2) Reverse Neuromuscular blocking drugs used for Anesthesia
30
What are the main uses for Muscarinic Agonists?
(1) constrict pupils
| (2) promote salivation
31
What are the main uses for Muscarinic Antagonists?
* dilate the pupils
* decrease oral secretions
* increase HR
* dilate bronchioles
* treat incontinence
* relax GI spasms
* treat movement disorders (Parkinsons)
* to treat poisoning of insecticide or chemical warfare (ATROPINE)
32
What is the effect of Atropine on the bladder?
Relaxes bladder & GI (constricts sphincter)
Atropine is a Muscarinic Antagonist and causes mimic of SNS
33
What is the effect of Pilocarpine on the bladder?
Contracts bladder & GI (relaxes sphincter)
Pilocarpine is a Muscarinic Agonist and causes mimic of PNS
34
Who should NOT receive a B2 Antagonist?
Asthmatics
B2 Antagonist will constrict the bronchioles
35
Where are NE and E active?
E is released from adrenal medulla and circulates blood stream (conc is low)
NE is released into a synapse (high conc)
36
What is Isoproterenol?
Iso-pro-terenol
Pure a1 agonist
Structurally similar to E
37
What is Phenylephrine?
Phenyl-ephrine
Pure a1 agonist
Can be administered locally to act on a specific site
38
Circular Iris muscles
| contracts to cause ...
```
Pupil constrcition
(miosis)
```
39
Radial Muscle
| contracts to cause ...
Pupil dilation
| Mydriasis
40
Cillary Muscle
| contracts to cause ...
accomadation of near/far vision
41
Single-unit Smooth Muscle
Examples...
GI tract
Uterus (at time of labour), s
Small diameter blood vessels (<200 μm),
Numerous Gap junctions, cells behave electrically and mechanically like a single unit.
42
Multi-unit Smooth Muscle
Examples...
```
Large airways
Large arteries
Uterus (other than labour)
Iris
Pilomotor muscles in the skin.
```
No gap junctions
Cells are electrically ISOLATED.
APs do not occur in these cells.
43
What does Smooth Muscle NOT have?
Troponin
44
How can Ca2+ accumulate in the myoplasm of smooth muscle?
(1) Direct Entry / Electrochemcial
(2) Ca-induced Ca release
(3) Pharmaco-mechanical Coupling
45
What is Hyperemia?
Increased blood flow to tissues
46
Effect of Ca2+ on smooth muscle cell
Progression of Events
Ca binds to Calmodulin
Ca-Calm complex DE-phosphorylates (activates) MLCK which then phosphorylates the myosin head. Myosin then binds to actin.
(this gets tropomyosin out of the way)
(Myosin Like Chain Kinase)
47
What happens if we remove Ca?
If we remove Ca2+ the smooth muscle will not relax
48
What is needed for the muscle to relax?
To make the muscle relax we must hyrdolyze the Myosin via MLCP
(Myosin-like Chain Phosphatase)
49
How is sympathetic tone achieved?
MLCP removes Phosphate from myosin.
Dephosphorylated myosin will continue through the contraction cycle at roughly 1/20th the rate.
There is always some MLCK present to keep some measure of contraction.
50
How does MLCK becomes inactivated?
MLCK is INACTIVE when phoshorylated by:
PKA (B-agonists)
PKG (NO, Atrial Natri-uretic Peptide)
51
When is MLCP inactive?
MLCP is inactive when phosphorylated. This can occur by:
***Removing P from myosin
***Rho Kinase (NE, AT-II, E-1)
(Pharmaco-mechanical coupling)
52
What IS Pharmacomechanical Coupling?
Change in tension in the muscle cell without changes in membrane potential
Via Rho-Kinase, certain ligands can inactivate MLCP. This causes vasoconstriction WITHOUT a there having been a membrane potential.
(only smooth muscle does this!)
53
How much Ca2+ is present in the SR of smooth muscle cells?
Very little. Becomes depleted rapidly and therefore, extracellular Ca is soon required.
54
How can Ca2+ accumulate in the myoplasm of smooth muscle?
(1) Direct Entry / Electrochemcial
(2) Ca-induced Ca release
(3) Pharmaco-mechanical Coupling
55
How can Ca2+ enter directly?
(1) Ca2+ leak channels
(2) Voltage gated
(3) Receptor gated
56
What is Ca-induced Ca release?
Ca2+ in the myosplasm binds to RyR-2 receptors on the SR to release MORE Ca2+
57
What is the difference between RyR-1 and RyR-2?
RyR-1: Skeletal Muscle
(makes physical contact with Ca channel)
RyR-2: Smooth Muscle
(does not make physical contact ... called Ca induced Ca release)
58
What is the progression of events that occurs in Pharmaco-Mechanical coupling?
```
Ligand binds to receptor.
Activates G Protein
Activates PLC
Activates IP3 & DAG
IP3 releases sequestered Ca from SR.
```
59
SO .... what is the mechanism by which Angiotensin II causes vasoconstriction?
Ang-II is a ligand that binds to smooth muscle cell receptor.
60
What is PL?
Phospho-lambon (PL)
| When in the de-phosphorylated form, PL inhibits the action of SERCA (SR Ca ATPase)
61
What is the result of the action of active PL
Ca-ATPase will NOT be operational. Therefore, Ca will not be taken back into the SR by SERCA. Myosplasm concentration will stay high.
Explanation:
Activated (dephosphorylated) PL inhibits the Ca-ATPase pumping Ca back into the SR.
62
How can PL be inactivated?
Phospholambin can be turned off by being phosphorylated
Done by PKA or PKG
63
SO, what is the result of PKA and PKG?
(1) Inactivates MLCK
RESULT: prevents contraction)
(2) Inactivates PL
RESULT: Ca is shoved back in the SR via SERCA
64
What is the relatiomship between SERCA & PL?
When activated (dephosphorylated), Phospholambin prevents SERCA from pumping Ca back in SR.
65
Is the uterus Single or Multi Unit Smooth Muscle?
Normally Multi-unit, BUT, during the labor it can turn into a single unit to cause more uniform and powerful contractions.
66
Vascular Smooth Muscle is almost entirely under the control of ....
Postganglionic Sympathetic Neurons
| very little parasympathetic
67
ATP concentration...
| Smooth vs Skeletal Muscle
Smooth Muscle can have large changes of of ATP conc
Skeletal Muscle: stays very consistent
68
Ligand Gated Channels In Smooth Muscle
(1) K-ATP Channel
(2) Ca-activated K Channel
(3) Purinergic
69
Ligand Gated Channels In Smooth Muscle:
| (1) K-ATP Channel
Ligand: Intracellular ATP
When ATP is present, it binds to receptor and prevents K+ export
When ATP is not present, K+ exits... hyperpolarization ... closes Ca channels ... relaxation
70
Ligand Gated Channels In Smooth Muscle:
| (2) Ca-activated K Channel
Senses intracellular Ca conc.
High Ca conc ... channel opens ... K exits ... hyperpolarization ... closes Ca channels ... relaxation
71
Ligand Gated Channels In Smooth Muscle:
allows Na and Ca to ENTER the cell
Depolarizes the cell and opens voltage-gated Ca channels.
Responsible for the early, fast, phase of smooth muscle contraction.
72
During Sympathetic Activation, what progression of events occurs in the cutaneous vessels?
*Varicosities release ATP & NE
ATP:
(1) ATP opens lingand gated channels
(2) Na & Ca enter cell
(3) More Ca enters (via RyR-2)
(4) MLCK activated
(5) Increased Sympathetic Tone
NE:
(1) NE binds to a-1 adrenergic receptors
(2) PLC ... IP3 ... Ca released from SR
73
Mydriasis vs Miosis
Miosis:
Constriction of pupils
Mydriasis:
dilation of pupils
74
What occurs at the axon hillock?
This is the location where action potentials are initiated
75
Oligodendrocytes
VS
Schwann cells
Oligodendrocytes (CNS)
can myelinate multiple axons
```
Schwann cells (PNS)
can only myelinate one axon
```
76
How and where is Ach synthesized?
synthesized from the condensation of acetyl-CoA and choline
occurs in motor neurons and their axons
77
In order to make Ach, where does the motor neuron get acetyl-CoA and choline?
Acetyl-CoA: from inside cell
Choline: from ECF
78
What is a long-term compensation to blood loss?
| weeks
Synthesis of Eryrthropoietin
occurs weeks after blood loss to help replace hemoglobin loss
79
How does the rate of firing from the carotid & aortic receptors correlate to arterial pressure.
Rise and fall together
An acute fall in arterial pressure results in a decrease in firing of the afferent nerves from the carotid sinus baroreceptors and thus, a reflex increase in arterial pressure and heart rate
80
Where do the baroreceptors first synapse?
The baroreceptor afferents first synapse in the cardiovascular centre of the brain, at the Nucleus of the Tractus Solitarius (NTS), which is in the medulla.
81
Baroreceptors respond to:
Deformation (stretch)
82
Why does a karate chop to the neck result in fainting?
The brain perceives an increase in BP via carotid sinus and aortic arch baroreceptors
Leads to a decrease in BP, causing fainting
83
What steps are involved in smooth muscle contraction>
(1) Ca binding to calmodulin
(2) Ca-calm binding to MLCK
(3) Ca-calm-MLCK phosphorylating myosin
(4) Myosin binding to actin
84
What does Smooth Muscle NOT use?
troponin
85
What is the effect of Endothelial-1 on smooth muscle?
E-1 causes Rho kinase to phosphorylate MLCP
Therefore ... turns off the inhibitor of contraction
86
Which receptors is primarily responsible for inhibiting production of cAMP?
a1
87
When are the different G proteins used?
Gq: a1 - PLC pathway
Gi: a2 - inhibit cAMP
Gs: B1&B2 - activate cAMP
88
muscarinic agonist
Beta-2 antagonist
What is their effect on:
(1) bronchioles?
(2) muscle vasculature?
(3) bladder?
Both cause:
bronchoconstriction
bladder constriction
Beta-2 antagonist would cause vasoconstriction in muscles
muscarinic agonist would NOT cause
vasoconstriction in muscles
89
Man has difficulty peeing ... what are we going to do?
a1 causes urinary sphincter constriction
Therefore, prescribe an a1 antagonist
90
What is the effect of alpha-1 stimulation at the uterus?
contraction
91
What is the effect of beta-1 blockade at the liver?
No major effect
92
What are the upper limits of normal diastolic and systolic blood pressure (DBP and SBP) with the patient seated and at rest?
140 / 90
93
Oligodendrocytes vs Schwann Cells
Which cells can myelinate multiple axons?
Oligodendrocytes:
can multiple many axons
Schwann cells:
can support many unmyelinated axons, however, when they produce myelin, are limited to ONLY ONE axon
94
What is the pathway of the baroreceptor afferents?
Synapse & and are integrated in the NTS of the MO
Then, they are relayed to the following:
* *Medulla (N. Ambiguus)
* *Hypothalamus
* *Cerebellum
95
True of False:
In some blood vessels, there are spontaneous depolarizations that resemble those in the sino-atrial (SA) node; this excitation spreads from cell to cell, producing rhythmic contractions.
TRUE!
This phenomenon can be described by the term "automaticity." Because of automaticity, some vessels retain a degree of tone even when the nerve supply is interrupted. This is referred to as "basal tone."
96
Do veins have smooth muscle?
YES,
| This can help regulate the filling pressure of the heart
97
True of False:
In smooth muscle, muscle contraction does not use ATP
FALSE
Smooth muscle uses ATP in muscle contraction.
98
True of False:
Smooth muscle uses crossbridge cycling, which is also used in striated muscle
TRUE
99
In a normal healthy individual, from a sitting position to an upright position, what would you expect to happen to the diastolic blood pressure (DBP) and heart rate?
DBP increases; heart rate increases
In the upright posture, there is decreased venous return and decreased stroke volume, which leads to decreased cardiac output. The decreased SP leads to a REFLEX increase in DP (due to increased peripheral vascular resistance) and HR increases.
