Physiology Flashcards
(147 cards)
1
Q
Anatomic and physiological dead space
A
Anatomical dead space: conducting zones of the lung - ventilation and no blood flow ~150mls, increases with large inspirations because of
the traction or pull exerted on the bronchi by the surrounding lung parenchyma.
Also depends on the size and posture of the person.
Functional - disease
Physiological - both - parts of lung with ventilation but no perfusion, volume of the lung that does not eliminate CO2
2
Q
Why is volume physiological deadspace important
A
greater total ventilation an individual must generate to ensure an adequate amount of air enters the alveoli to participate in gas exchange
3
Q
Cardiac conducting system
A
SA, AV, LBB, RBB
SA node - junction of the SVC and RA
AV node - R post interatrial septum.
3 bundles of atrial fibres connect SA to AV
AV node is continuous with the bundle of His, which gives off LBB and RBB
LBB divides into an anterior and a posterior fascicle.
Branches and fascicles run subendocardially down septum and come
Purkinje fibers spread to all parts of the ventricular myocardium.
4
Q
Cardiac cycle phases vs ECG
A
P wave : Atrial depolarisation
PR interval : AV conduction
QRS : Ventricular depolarisation
ST segment: plateau portion of ventricular depolarisation
QT : ventricular action potential
T wave: Ventricular repolarisation
5
Q
Membrane changes in infarcted myocytes
A
Rapid repolarisation due to accelerated opening of K+ channels (seconds to few minutes)
Decreased resting membrane potential due to loss of intracellular K+
Slow depolarisation of the affected cells compared to surrounding normal cells
6
Q
LV changes and cardiac cycle
A
Atrial systole: Contraction of atria, blood flows into R and L ventricles via open AV valves
Isovolumetric ventricular contraction:
AV valves close, pulmonary and aortic remain closed. Ventricles are contracting without a change in volume
–> sharp rise in pressure.
Ventricular ejection: Aortic valve opens when pressure in LV exceeds the aortic pressure, 80mmHg. The stroke volume is ejected, LV peaks at 120mmHg
Isovolumetric relaxation: End of systole and beginning of diastole. Aortic valve closes once LV pressure below 80mmHg. AV valve remains closed. Rapid pressure drop, no change in volume.
Ventricular filling: AV valves open once vent pressures fall below atrial pressures. Blood flows into ventricles from atria.
7
Q
When does the aortic valve open and shut
A
opens once LV pressure exceeds aortic pressure at 80mmHg marking the end of isovolumetric contraction.
Closes once LV pressure drops below 80mmHg during isovolumetric relaxation.
8
Q
Factors affecting insulin secretion
A
Increased by: glucose, AAs, GIP, glucagon, theophyline, sulfonylureas
Decreased by: somatostatin, hypokalaemia, beta blockers, thiazides, alpha agonists (adr and norad)
9
Q
Principle actions of insulin
A
Seconds: increased glucose and AA uptake cells, inc K uptake cells
Minutes: inc protein synth, dec protein degradation, activation glycolytic enzymes
Hours: inc mRNA for lipogenic enzymes
10
Q
Effects of insulin on carbohydrate regulation and metabolism in tissues
A
*Adipose: inc glucose entry, inc fatty acid synthesis, inc K uptake
*Muscle: inc glucose entry, inc AA uptake, inc protein synthesis
*Liver: decreased ketogenesis, inc protein synthesis, dec gluconeogenesis
11
Q
What are baroreceptors and where
A
Stretch receptors
Aortic arch and carotid sinus
Atria
12
Q
MOA of baroreceptors
A
Stretch leads to neuronal discharge
inhibits sympathetic and increases vagal
Leads to vasodilation, dec BP, bradycardia
13
Q
Normal CSF pressure
A
10-25 cm
14
Q
Mechanism of fever
A
toxins act on monocytes, macrophages and kupffer cells –> cytokine release
Endogenous pyrogen e.g. IL6 and TNFalpha independently cause fever
CNS pyrogens act on hypothalamus causing PG release
15
Q
Causes in reduced preload
A
Dec venous return - dec blood volume, venous pooling, gravity, vasodilation
Dec ventricular filling - inc thoracic/ pericardial pressure, dec ventricular compliance, dec filling time tachycardia, loss atrial kick AF
16
Q
Potassium reabsorption in collecting ducts
A
H-K ATPase reabsorb K in exchange for H
17
Q
How does aldosterone increase K secretion in urine
A
Aldosterone secretion triggered by high K
Acts on DCT and cortical collecting duct
Stimulates NaKATPase BLM
Causes K and Na channels to form apical membrane principal cells
18
Q
Transport CO2 in blood
A
90% bicarb
5% carbamino compounds
5% dissolved
19
Q
Chloride shift
A
- Ionic dissociation carbonic acid to bicarb and H in red cell
- Bicarb diffuses out, H+ stays in as impermeable to cations
- Cl- diffuses in to maintain neutrality
20
Q
Draw and lael pressure volume curve LV
A
Y axis pressure 10 - 120
X ais volume 50 - 130
21
Q
Arterial supply to cardiac conducting system
A
SA node- RCA 60%, circumflex 40%
AV node and bundle- RCA, AV nodal artery
Right and Left Bundles and Purkinje fibres- LAD
22
Q
Consequences impaired renal function
A
Proteinuria and hypoalbuminaemia - inc perm glomerular capillaries
Uraemia - impaired exc products protein breakdown
Acidosis and hyperkalaemia
Abnormal Na handling with inc retention
23
Q
Cause impaired ability kidney to conc urine in renal failure
A
disruption counter current mechanism
loss of nephron function
24
Q
Synthesis of ACh at NMJ
A
- synthesized in pre synaptic terminal and stored in synaptic vesicles
- acetyl co A + choline catalysed by choline acetyltransferase
25
Mechanism ACh release at NMJ
Impulse at moto neuron ending causing Ca channel opening
Ca influx triggers ACh release into synaptic cleft
26
ACh after release into synaptic cleft
Binds to nicotinic receptors -> Na entry and depolarising end plate potential
Broken down by ACHase to choline and acetate
Choline reuptake into presynaptic terminal
27
Location of hydrogen secretion renal tubules
PCT - NaH exchanger
DCT and CD - Alsosterone stimulated proton pump and HKATPase
28
Limiting pH urine and where is it reached
4.5
CD
possible due to buffers
29
Sodium reabsorption kidney
60% PCT NaH exchange + cotransporters
Thick asc - Na K Cl
DCT NaCl co
CD ENaC
30
Mechanisms to enhance Na excretion
Increased pressure ECH -->
- pressure natriuresis
- Inc ANP
- suppression AT II
- Stretch in RA and pulm -> inhib sympathetic outflow
31
Pacemaker action potential
4 Pre potential - reduced K efflux and Ca influx
0 Ca influx ligand gated
3 K efflux
32
Counter current mechanism
concentration mechanism to maintain a gradient of increasnig osmolality along medullary pyramids to allow concentration of the urine
Gradient produced by countercurrent multipliers in LOH and maintained by vasa react as counter current exchangers
1. Active transport NaCl out of thick LOH
2. Water reabsorbtion thin desc LOH into hyperosmolar medullary space
3. There is an increase in osmotic gradient between interstitial fluid and tubular fluid
4. Vasa recta act as exchanger maintaining gradient
33
Coronary blood flow at rest
5% CO (10% O2), 250ml/m
34
Mediators coronary vasodilation
Hypoxaemia, K, H, lactate, CO2
Adenosine, PGs
35
Receptors governing coronary blood flow
alpha receptors - constrict
Beta - vasodilate
Cholinergic - vasodilate
36
Brain perfusion during injury
Increased MAP to increase CPP
CPP=MAP-ICP
37
Definition diffusion and perfusion limited
perfusion - partial pressure either side membrane equalises quickly, no further diffusion into blood unless perfusion rate increases
diffusion - partial pressure of as does not achieve equilibrium across membrane in time blood spends in pulm capillaries
38
Definition GFR
Amount of fluid filtered by glomerulus per unit time
39
Factors affecting GFR
capillary bed size moderated by mesangial cells
hydrostatic and osmotic pressure gradients STARLING FORCES
BP
Age
Afferent/ efferent arteriolar constriction
40
Substances acting on mesangial cells to change GFR
Inc - ANP, dopamine, PGE2
Dec - Norad, ADH, histamine
41
Sympathetic and parasymp action on cardiac pacemaker
symp - NA B1 inc cAMP, opens L channels inc slope prepotential
para - ACh M2 increased K efflux, decreased Ca influx DECREASED SLOPE PRE POTENTIAL
42
Factors increasing and decreasing lung compliance
Increase - emphysema (due to loas elasticiyy), and age
Decrease - fibrosis, pulmonary oedema, unventilated lung, pulm HTN
43
Physiological effects surfactant
1. increases compliance
2. decrease WOB
3. Keeps alveoli open
4. Keeps lungs dry
44
Physiological effects of blood loss
Immediate - baroreceptor decreased firing, HR, BP, chemoreceptors causing vasoconstriction
Hours to days - inc RAAS, decreased UO
10 days - inc RBC production EPO
45
Stretch reflex components
Monosynaptic reflex
Afferent nerve, monosynapse on motorneuron, efferent nerve, effector
46
Mechanism atrophy
Decreased protein synthesis
Increased protein degradation
Autophagy
47
Causes of atrophy
Denervation
Decreased blood supply
Disuse
Ageing
Inadequate nutrition
Loss of endocrine stimulation
48
Frank starling curve
Y - SV
X - LVEDV
left - inotropes, catecholamines
right - HF (intrinsic depression), hypoxia, vagal stimulation
49
Factors affecting airway resistance
poiselles - 8Lvisc/pieR4
Laminar flow
Turbulent higher reynolds
Highest medium size bronchi
Beta adrenergic
50
Nerve action potential
1. depolarising stimulus -> voltage gated sodium channel open
2. Threshold potential is reached (-55) - increased Na open and further depolarisation causing upstroke AP
3. Membrane potential moves closer to equilibrium potential for Na (+60)
4. Voltage gated Na become inactive and then resting
5. Opening voltage gated K leads to repolarisation followed by hyperpolarisation
6. Membrane returns to resting (-70)
51
Events following motor end plate discharge
Activation Ca channels with influx
ACh released synaptic cleft bind post synaptic nicotinic
Inc Na and K conductance end plate --> AP
Calcium release from SR
Binding Ca to troponin C uncovering binding site myosin binding site actin
Actin myosin slide - muscle contraction
52
Metabolism bilirubin
Bound to albumin in circulation
Dissociated in liver, free bilirubin enters liver cells
GLUCORONIDATION Conjugated in liver to bilirubin diglucoronide
Transported to bile ducts and intestine
In intestine bacteria form unconjugated bilirubin and urobiligen
Some excreted gut, some reenters enterohepatic circulation, some urobiligen excreted kidney
53
Factors determining renal blood flow
Perfusion pressure
Renal artery effects
Renal nerves
Autoregulation
54
Regulation calcium
1,25 dihdrocolecalciferol increases Ca absorption GIT + Kidney
PTH mobilises Ca from bone and increases reabsorption kidneys
Calcitonin inhibits bone resorption and increases excretion kidneys
55
Regulation of synthesis of 1,25 dihydrocholecalciferol
Formed in kidney by 1alpha hydroxylase
Low Ca --> stimulation 1alpha hydroxylase
High Ca inhibits
56
Physiological causes hypoxaemia
Hypoventilation
Shunt
VQ mismatch
57
Measuring VQ mismatch
Alveolar/ arterial PO2 difference (A-a gradient)
58
Physiological effects dehydration
inc HR dec BP
Inc ADH + RAAS
dec UO and GFR
59
Definition autoregulation
Capacity tissue to regulate own blood flow at relatively constant rate despite moderate changes in perfusion pressure
Achieved by altering vascular resistance
60
Mechanisms autoregulation
Myogenic - contractile response smooth muscle to stretch
Metabolic - vasodilator metabolites
Endothelial products - endothelin constrict, NO dilate
Neural - sympathetic and parasympathetic
61
Local factors leading to vasodilation
Hypoxia, hypercarbia, acidosis lactate, hyperkalaemia, NO, PGs, histamine
62
Effects of angiotensin II
Arteriolar vasoconstriction via AT1 receptors
Acts on adrenal cortex --> aldosterone --> sodium and water reabsorption
63
Factors increasing and decreasing TSH
TRH - hypothalamus, TSH, ant pit
Inc - cold,
Dec - heat, glucocorticoids, somatostatin
64
Effects thyroid hormones
Cardiac - inc HR dec BP
CALORIGENIC - inc met rate and O2 consumption
Adipose - catabolic, lipolysis
Muscle - catabolic , proteolysis
Bone - promotes development
Neuro - brain development
Gut - metabolic, carb absorption
Cholesterol - LDL receptor formation
65
Body response to hot/ cold
Hot:
Dec production - reduced appetite apathy
Inc loss - vasodilation, sweating, resp
Cold:
Dec loss - curl in ball, horripolation, vasoconstriction
Inc production - shivering, hunger
66
Fluid tonicity regulation
Inc plasma osmotic receptors - sensed ant hypothalamus osmoreceptors + thirst is increased
ADH release inc --> V2 receptors renal leading to aquaporin insertion and water resoption
67
Stimulators ADH release
Decreased ECF volume, pain, emotion, nausea and vomiting, standing, carbamazepine
68
Measuring dead space
Anatomical - fowler
Physiological - bohr
69
Mechanism of venous return to the heart
Via thoracic pump - insp generates -ve intrathoracic pressure and positive intraabdominal
Venous valves allow one way flow
With heart beat valves sucked down and blood pulled in
Compression of veins by arteries and muscles aid venous return
70
Causes inc and dec CVP
Inc - positive pressure vent, inotropes, fluid resus
Dec - fluid loss, loss myocardial lump function, poor vent filling (arrhythmia)
71
Mean CVP
6-8cm h2o
4.6-6mmHg
72
Role of RBCs in CO2 transport
Contains carbonic anhydrase
Chloride shift occurs
Haldane effect
Carbamino compound
73
Absorption iron
Gastric acid reduces ferric to ferrous
Further reduced by ferric reductase
Predominantly duodenum
Uptake by DMT transporter to enterocyte
Dietary heme also taken into enterocyte
Transported to blood by ferroportin
74
Transport of iron in plasma
Converted to ferric form and bound to transferrin
75
Factors reducing iron absorption
Dietary - oxalates and phosphates bind making insoluble
Medical/ surgical - coeliac, gatrectomy
Physiological - high iron store, recent high intake, low erythropoesis
Drugs - antacids
76
Location iron
70% hb
27% ferritin
3% myoglobin
tiny mount on transferrin
77
Location iron
70% hb
27% ferritin
3% myoglobin
tiny mount on transferrin
78
Factors affecting glucose homeostasis
Absorption in intestine
Uptake in periphery - muscle, brain, liver
Reabsorption kidney
Gluconeogenesis liver
79
Glucose homeostasis in absence insulin
Decreased peripheral uptake
Reduced uptake in liver
Increased glucose output liver
Reduced glycogen synthesis
80
Glucose homeostasis in absence insulin
Decreased peripheral uptake
Reduced uptake in liver
Increased glucose output liver
Reduced glycogen synthesis
81
Mechanism glucose causes insulin release
Glut 2 transporters beta cells
Converted to pyruvate and then glutamate priming insulin granules
ATP production triggers ca influx and insulin release
82
Physiological reaction to blood loss
EARLYDecreased baroreceptor firing
Chemoreceptor activation leading to peripheral vasoconstriction
MINS/HRS Renin angiotensin system activation
LT renal compensation via aldosterone and inc salt intake and erythropoeisis
83
Physiological causes hypoxaemia
Hypoventilation, VQ mismatch, shunt, impaired diffusion
84
How does VQ inequality lead to hypoxaemia
Low VQ have effluent blood low O2
High VQ have high effluent O2 but due to non linear O2 dissociation curve to not compensate for the low VQ areas
85
Why does CO2 remain normal in VQ mismatch
Dissociation curve linear
Inc CO2 stimulated chemoreceptors leads to inc ventilation
86
Physiological effects of dehydration
Dec BP, inc HR
Inc ADH, dec UO, dec GFR
Thirst
87
Activators of renin angiotensin system
Due to decreased BP/ ECF or sympathetic activity
Haemorrhage
Dehydration
Heart failure
Cirrhosis
Sodium depletion
Diuretics
Pain or fear
88
Micturition pathway
Sacral spinal reflex
Facilitated and inhibited by higher centres, subject to voluntary control
150 urge, 400 reflex contraction
Stretch receptor bladder wall afferent to pelvic nerves
Efferent parasympathetic fibres
Pudendal voluntary control external urethral sphincter
89
Mechanisms absorption and secretion
Cotransporters
Exchangers
Ion channels
Passive and facilitated diffusion
90
Factors within glomerulus affecting GFR
Surface area of capillary beds within glomerulus
Permeability glomerular capillaries
Hydrostatic pressure glomerulus
Oncotic pressure within glomerulus
Hydrostatic pressure bowmans capsule
Number functioning renal corpuscles
91
Alveolar gas equation
To measure fall in O2 and rise CO2 that occur in hypoventilation
PAO2 = PiO2 - PACO2/R (resp quotient)
A/a gradient used to measure va inequality
92
Definition VQ ratio
Conc of O2 in any respiratory unit determined by ventilation - amount air getting to alveolus
And perfusion - blood flow through pulmonary capillary
0.8
93
What are urinary casts
Proteinaceous material precipitated in tubules, washed into bladder
94
Physiological effecta glucocorticoids
Catecholamine effecta of vasopressor effects and inc vascular reactivity
Resp - bronchodilation
Metabolic - protein catabolism, hepatic glycogenolysis and gluconeogenesis, decreased ADH
ADRENAL SUPRESSION IF EXOGENOUS
Immunological - decreaaed inflam response and leukocyte reactivity
Neuro - EEG slowing and personality changing
95
Glucocorticoid secretion regulation
Secreted from adrenal cortex
Dependant on ACTH from anterior pituitary (which is dependant on CRH from hypothalamus)
Glucocorticoids cause negative feedback to hypothalamus and ant pit causing reduced ACTH
96
Definition UMNs
Corticospinal neurons that innervate spinal motor neurons
97
Physiological basis clonus
Loss of descending cortical input to inhibitory Renshaw cells
Therefore loss inhibition of antagonists
Repetitive sequential contractions flexors and extensors ankle following muscle stretch
98
Haldane effect
Increased affinity of deoxy hb for CO2 and binding of O2 to Hb reduces it's affinity for CO2
Allows removal of CO2 from O2 consuming tissues
Promotes the dissociation of CO2 from Hb in the presence of O2 e.g. lungs
99
Factors increasing thirst
Increase in plasma oncotic pressure sensed by osmoreceptors anterior hypothalamus
Reduced ECF volume due to eg haemorrjage or dehydration, sensed by baroreceptors
Psychological - psychosis
Prandial drinking
100
Glucose handling kidney
Freely filtered glomerulus
Reuptake proximal PCT
Secondary active transport
Apical SGLT2 transporter and basolateral GLUT 2 fascilitated diffusion
Excreted in urine in renal threshold reached
101
Reason for normal Aa gradient
Normally 5-10mmhg
Alveolar O2 at apex high - 40mmhg
Howevee most blood flow at base where alveolar O2 low thus dec art O2
Also do to the effect of shunting of bronchial and coronary blood
102
Measuring lung volumes
Spirometry fev1 and fvc
Ventilator tv
Helium dilution ory body plethysmograohy for TLC FRC RV
103
Mechanisms causing tachyarrhythmias
Increased automaticity
Reentry circuits
Accessory pathways
104
Factors predisposing to increase automaticity heart
IHD
Structural heart disease
Scar tissue
Electrolyte abnormalities
Channelopathies
105
Factors affecting cerebral blood flow
MAP and MVP at brain level
ICP
Viscosity of blood
Local constriction / dilation cerebral arterioles
106
How is renal blood flow measured
Fick principle - amount of substance taken up per unit time / AV conc difference
PAH used to measure effective renal plasma flow
/0.9 for actual renal plasma flow
RBF = rpf x 1/1-hct
107
Define RMP
Potential difference across cell at rest.
As result seperation of positive and negative electronic charges
Inside -ve
Neuron -70
108
Explain how RMP is created
Dependant Na and K
Na K ATPase 3 Na out 2 K in
Diffuse opposite way down conc grad
More permeable to K at rest so closer to equilibrium potential K
109
Explain how RMP is created
Dependant Na and K
Na K ATPase 3 Na out 2 K in
Diffuse opposite way down conc grad
More permeable to K at rest so closer to equilibrium potential K
110
Why cell more exciteable in hyperkalaemia
RMP Closer to threshold potential
111
Factors affecting oxygenation in an alveolus
V
Q
Diffusion across blood gas barrier
112
Oxygen uptake along pulmonary capillary
Due to alveolar pulmonary capillary O2 gradient (100 / 40mmhg)
RBC transit time 0.75 seconds
O2 uptake in 0.25 seconds and is perfusion limited
Alveolar and end capillary O2 difference minimal
113
Affect of hypoxia on oxygenation
Reduced alveolar capillary O2 gradient so decreased diffusion
114
Definition mesangial cells
Contractile cells in the glomerulus that regulate GFR
Also secrete ECM and involved in the progression glomerular disease
115
How do the kidneys respond to acidosis
Aim to return pH to normal
Secretion (active) H+ in exchange for Na
Bicarb active resorption
Buffers for greater secretion
116
How do the kidneys respond to acidosis
Secretion H+ in exchange for Na
Bicarb active resorption
117
Principle functions of the liver
Bile formation
Synthesis - proteins, albumin, coag factors
Inactivation and detoxification
Vitamin absorption
Metabolism
Immunity
118
How hypotension activates renin angiotensin system
reduced perfusion pressure afferent glomerular arteriole leads to renin release by JGA
119
Carbon dioxide dissociation curve
Y C CO2 ml/L 400-600
X P CO2 20-80
Hb oxygenated curve below Hb reduced
arterial 40, venous 48
120
Role of ADH in dehydration
water resorption in CD via aquaporin insertion
vasoconstriction
121
Where is calcium stored
99% calcium
Plasma bound or unbound
122
How does bone resorption occur
Osteoclasts develop under influence of RANKL
Attach to bone via integrins
Causes increased hydrogen in cell causing dissolution hydroxyappetite
Protease break down collagen
123
Definition referred pain
Irritation visceral organ causing pain in a distant somatic structure
124
Factors affecting CO
SV - preload (stretch prior to contraction) and afterload (resistance to flow) of heart
Intrinsic contractility myocardial cells
HR - sympathetic and parasympathetic
125
Phases valsalva
1 - initial, inc intrathoracic pressure and LV output
2 - strain, decreased venous return, inc heart rate, Dec sv
3 - release - increased venous return
4 - overshoot with Dec symp output and reflex Brady
126
Factors affecting work of breathing
Elastic forces of the lungs and chest wall - inc by high tidal volume and reduced compliance
Viscous resistance of the airway and tissues - inc in airway constriction and inc air viscosity
127
How does urea reach the interstitium
Facilitated diffusion
128
Effects of exercise on the respiratory system
Increased gas exchange with Dec vq mismatch
Inc vent with inc TV, RR and minute volume
Inc Pulmonary blood flow with Dec Pulmonary vascular resistance
129
Urea handling kidney
Freely filtered
Half resorbed pct
Half secreted back into LOH
Half resorbed back CD
130
Factors causing increased and decreased ATII
Inc due to catecholamines, sympathetic activation, PGs
Dec with in na at macula densa, increased Afferent arteriolar pressure , ADH
131
Kidney BP autoregulation
90 and 210
132
Definition and theory referred pain
Irritation visceral organ causing pain in distant somatic structure
Convergence projection theory due to convergence of somatic and visceral fibres, unable to be distinguished in sensory cortex
133
What is EPO
Glycoprotein produced by the kidney
Stimulates red cell precursors to proliferate
Used in anemia of chronic renal failure
SE HTN and thrombosis
134
Where does the acidification of urine occur
In the pct, dct and collecting ducts
135
Descending vs ascending g LOH
Descending becomes hypertonic
Ascending becomes hypotonic
136
Tubuloglomerular feedback in nephron
Maintain constancy in load to distal tubular
Macula dental in ascending LOH senses rate of flow and feeds back to filtration rate in glomerulus
137
Synthesis of T4
Iodine amd throglobulin combine
Form DIT and MIT
Combine to form T3 and T4
138
Functions vitamin D
Increases calcium absorption GI tract
Decreases excretion in kidney
Increases osteoblasts
139
ECG hypokalaemia
Long pr
St depression
T wave inversion
U waves
140
Smooth muscle contraction
ACh binds muscarinic
Calcium influx
Activation calmidulin dependant light chain kinase
Myosin binds actin and causes contraction
141
Smooth muscle contraction
ACh binds muscarinic
Calcium influx
Activation calmidulin dependant light chain kinase
Myosin binds actin and causes contraction
142
Locations nicotinic and muscarinic receptors
Nicotinic NMJ and CNS
Muscarinic smooth muscle and glands
143
Transmission pain from periphery to brain
Nerve ending
A delta and c fibres to dorsal horn
Ventrolateral system to thalamus
Then to cerebral cortex
144
Factors controlling blood flow to myocardium
Local factors controlling radius vessels- hypoxia, co2
Neurogenic factors controlling radius vessels
Pressure differences
145
Enzymes secreted from exocrine pancreas
Trypsin - proteins
Lipase - triglycerides
Amylase - starch
Elastase - elastin
146
Water and electrolyte absorption GI tract
After meals fluid uptake due to couples transport of nutrients
Between meals na/h and cl/hco3 exchangers
147
Water and electrolyte secretion gi tract
Cl secretion continuous SI and colon
Cftr channel
Endogenous secretion 7L water
