Physiology Flashcards
1
Q
Which NO synthase (NOS) is located in endothelial cells?
A
NOS 3
2
Q
NO typically acts via which other 2nd messenger?
A
cGMP (direct activation of guanylyl cyclase -> Ca2+ influx -> cGMP activation
3
Q
What is the half life of a neutrophil?
A
6hrs
4
Q
What factors stimulate eosinophil maturation & activation?
A
IL-3, IL-5, GM-CSF
5
Q
Give 3 examples of organ-specific tissue macrophages
A
Kupffer cells (liver); pulmonary alveolar macrophages, microglia (brain)
6
Q
Only vasodilator/ vasoconstrictor fibres reach the liver (to both the portal vein and hepatic artery)
A
Vasoconstrictor (via 3rd-11th thoracic ventral roots/ splanchnic nerves to portal vein and hepatic sympathetic plexus to the artery)
7
Q
What is the normal portal venous pressure?
A
10mmHg (compared to 5mmHg for hepatic venous pressure)
*Think 0 in p0rtal
8
Q
List drugs that cause proliferation of hepatocyte smooth ER and thus increase hepatic glucuronyl transferase activity
A
Barbiturates, antihistamines, anticonvulsants
This increases conjugation of bilirubin to glucuronic acid
9
Q
The ___ is the only organ in which the complete urea (Krebs) cycle is expressed
A
Liver.
This occurs in the mitochondria and cytosol of hepatocytes
10
Q
Why is ammonia metabolism in the liver so important?
A
Otherwise it accumulates in systemic circulation, can cross the BBB and is toxic to the CNS
11
Q
The ___ membrane of cholangiocytes expresses GGT
A
Apical
12
Q
What are the 3 buffers to neutralise acid (H+) in the renal system, and where does each process predominately occur?
A
Ammonia (NH3 + H+ -> NH4): prox + distal tubules
Bicarb (HCO3- + H+ -> H2CO3 -> H2O + CO2): prox tubules
Dibasic phosphate (H(PO4)2- + H+ -> H2(PO4)-): distal tubules + collecting duct
13
Q
What is an annular pancreas?
A
Developmental malformation where head of pancreas ‘wraps around’ duodenum forming a ring and increasing risk of duodenal obstruction
14
Q
What is the first enzyme activated in acute pancreatitis?
A
Trypsin
15
Q
What is the mechanism of acute pancreatitis secondary to alcohol?
A
Alcohol stimulates contraction of Sphincter of Oddi, blocking off pancreatic duct
16
Q
What is the mechanism of hypocalcaemia in pancreatitis?
A
Fat necrosis of peripancreatic fat -> saponification (consumes calcium).
17
Q
What are the fat-soluble vitamins?
A
A, D, E, K
18
Q
What is the pathophysiology of raised ALP in cholecystitis (not due to duct obstruction)?
A
Epithelium lining gallbladder produce ALP -> when damaged (ischaemic/ inflammation) then more ALP is released into circulation
19
Q
What is a porcelain gallbladder?
A
(Dystrophic) calcification of gallbladder wall secondary to chronic cholecystitis. It will show up as radio-opaque outline of gallbladder; Risk factor for cholangiocarcinoma
20
Q
The brush border of intestinal epithelium is endowed with what substance?
A
Dense glycocalyx
21
Q
What are the 3 salivary glands?
A
Parotid, submandibular and sublingual glands
Overall they supply 1000-1500mL saliva/ day
22
Q
The saliva contains __ and ___ , which act as protective organic constituents
A
IgA and lysozyme
Saliva has 3 main functions
- digestion (esp starch): e.g. a-amylase
- protection: e.g. IgA, lysozyme + neutralize gastric acid (oral pH ~7.0)
- lubrication: e.g. mucin
23
Q
Saliva is rich in which ions?
A
K+, bicarb (in exchange for Na, Cl)
It is a hypotonic solution
24
Q
The [PNS/ SNS] is the most prominent control of salivary secretion
A
PNS
PNS is activated by sight/ smell/ thought of food and chewing. Acts via ACh at otic and submandibular ganglions
SNS slightly modifies saliva composition (more proteinaceous)
25
List the 4 main cell types in a gastric body/ fundus gland and what each secretes
1. Surface mucous cells - mucus, trefoil peptide, bicarbonate
2. Parietal cells - hydrochloric acid, intrinsic factor
3. Enterochromaffin-like (ECL) cells - histamine, motilin
4. Chief cells - pepsinogen, gastric lipase
26
Gastric hydrochloric acid sterilizes the meal and begins the hydrolysis process, especially of what dietary component?
Protein
27
Somatostatin inhibits which gastric cells?
G cells (in antrum), ECL cells (in gastric mucosa) and parietal cells (gastric mucosa)
28
List the 3 agonists for parietal cell acid secretion, the Rs they act on and the 2nd messengers they act through
Gastrin (CCK-B receptor) via Ca2+/ PLC
ACh (M3-R) via Ca2+/ PLC
Histamine (H2-R) via cAMP/ AC
All act on basolateral membrane, and ultimately increase apical H+/K+ pump. These act synergistically (greater than additive effect)
29
Pancreatic secretion is stimulated by ____ (via [2nd messenger]) and ____ (via [2nd messenger])
Secretin (via cAMP) and CCK (via PLC)
30
What are the nutritionally essential amino acids?
Valine, leucine, isoleucine, threonine, methionine, phenylalanine, tryptophan, arginine, lysine, histidine
31
What are the stages of mitosis?
1) Prophase
2) Metaphase
3) Anaphase
4) Telophase
5) Cytokinesis
32
Define the building blocks of RNA and DNA
Nucleoside = sugar (ribose or 2-deoxyribose) + N-containing base
33
The Na-K ATPase moves __ Na+ IN/OUT of the cell for every __ K+ IN/OUT of the cel
3 Na+ OUT for 2 K+ IN
34
Define osmolarity and osmolality
Osmolarity = number of osmoles per litre of solution
Osmolality = number of osmoles per kg of solvent
35
What is the isohydric principle?
All buffer pairs in a homogenous solution are in equilibrium with the same [H+]
36
What percentage of body is water?
60%
Approx 1/3rd is extra-cellular and 2/3rd intracellular
(~18% protein, 15% fat, 7% minerals in average young adult male)
37
True or false: bile is the only route by which the body can dispose of cholesterol
True
38
Bile acids are synthesised from ___ and secreted into bile conjugated to ___ or ___
Cholesterol
Glycine or taurine
39
What are the 4 bile acids, and where are each 'produced'
Cholic acid & chenodeoxycholic acid from liver
Deoxycholic acid and lithocholic produced in intestine by bacterial conversion
40
CCK is primarily produced in ___. List its main actions (4)
I cells of the small intestine mucosa
Actions
- Pancreatic juice secretion (enzyme-rich)
- Gallbladder contraction
- Sphincter of Oddi relaxation
Also trophic effect on pancreas, inhibit gastric emptying, enterokinase synthesis, ?SI/colonic motility
41
In the GI system, secretory fluxes of fluid are largely driven by active transport of __ ions into the lumen
Chloride
42
98% of fluid in the GIT is reabsorbed. The majority of reabsorption occurs in which part?
Jejunum
43
What is the pH of each of the following fluids: saliva, gastric juice, duodenum, pancreatic juice, bile
Approximately what volume of each is produced daily?
Saliva: ~7.0. 1-1.5L
Gastric juice: ~3.0; 2.5L
Duodenum: 6-7.0, 1L
Pancreatic juice; ~8.0. 1.5L
Bile: 7-8.0. 500mL
44
Where is the ‘Vomiting centre’ located?
In the reticular formation of the medulla
45
Where is the chemoreceptor trigger zone (CTZ) located?
Area postrema on the lateral walls of the 4th ventricle. Has D2 and 5HT3-Rs (this explains MoA of common antiemetics - ondansetron is a 5H3T-R antagonist, and chlorpromazine/ haloperidol are D2-antagonists)
46
Intestinal __ make the greatest contribution to increased surface area
Microvilli
47
List key hormones involved in gastric secretions, the cells they are produced by and location of these
Gastrin - G cells (gastric antrum)
Somatostatin - D cells (gastric antrum and pancreatic islets)
Secretin - S cells (proximal SI)
CCK - I cells (proximal SI)
GIP - K cells (proximal SI)
VIP - enteric neurons
48
Conduction velocity is increased by ___ and ___
Greater neuron diameter + myelination
49
Acidosis, hypotension and hypoxia cause cerebral [vasodilation/vasoconstriction]
VasoDILATION
50
What is normal intracranial pressure?
0-10mmHg
51
Catecholamine formation is usually by hydroxylation and decarboxylation of which amino acid?
Tyrosine
52
Where does noradrenaline synthesis occur?
In intracellular synaptic vesicles
(most other small-molecule transmitters are synthesised in the cytosol)
53
The adrenal cortex releases which hormones? The medulla? Which zones does each come from
Cortex - steroid hormones
- Glucocorticoids - zona fascicularis
- Mineralocorticoids - zona glomerulosa
- Androgens - zone reticularis
Medulla (chromaffin cells) - catecholamines (adrenaline, noradrenaline, dopamine)
54
ACTH originates from the ___
Anterior pituitary
55
Denser granules are found in adrenal medulla cells secreting adrenaline or [nor]adrenaline?
noradrenaline
56
What are the 3 zones of the adrenal cortex?
Zona glomerulosa (aldosterone-producing), zona fasciculate (cortical/ proges), zone retucularis
57
List common drugs/ classes that stimulate ADH release (min 5)
Anti-convulsants (carbamazepine, phenytoin, valproate)
Analgesia (morphine, duloxetine, pregabalin)
Barbiturates (phenobarbital)
Anti-depressants & tricyclics (citalopram, venlafaxine, amitriptyline)
Anti-psychotics
Cytotoxics & chemo drugs
Nicotine
Chlorpropamide
58
True of false: CO2 is more soluble in CSF than H+
True
It is rapidly converted to H2CO3 in the CSF
59
What is the normal tidal volume and physiological dead space volume?
Tidal volume - 500mL
Physiological dead space - 150mL
60
List 3 examples of transcellular water
Aqueous humor, CSF, synovial fluid
(water that has been processed by cells into special compartments)
61
Water content of fat is (HIGHER/ LOWER) than that of muscle
Lower
(% water of total body weight is inversely proportional with % body fat)
62
What is the most important buffer?
Bicarbonate
63
Which buffer is more effective at physiological pH - bicarbonate vs phosphate?
Phosphate (pK 6.8 compared to bicarbonate 6.1)
64
Describe the water/ ion permeability of the descending & ascending limbs of the loop of Henle
Thin Descending - water permeable
Thin ascending - water impermeable, ion permeable
Thick ascending - water impermeable, active ion transport
65
In the nephron, aquaporin-1 and aquaporin-2 are predominately located in which parts respectively?
Aquaporin-1: proximal convoluted tubule+ descending loop of henle
Aquaporin-2: collecting duct (ADH-responsive)
66
Sodium is actively transported out of all segments of the nephron except the ___
Descending thin loop of Henle
66
Sodium is actively transported out of all segments of the nephron except the ___
Descending thin loop of Henle
67
What is the action of aldosterone?
Acts on collecting duct to increase expression of ENaC, resulting in water & thus Na+ reabsorption
68
What is the action of ADH?
Acts on distal convoluted tubules & collecting duct to increase expression of aquaporin-2, resulting in water reabsorption
69
Loop diuretics inhibit ___
Thiazide diuretics inhibit ___
Loop - Na-K-2Cl cotransporter in the thick limb of ascending loop of Henle
Thiazide - Na-Cl cotransporter in distal convoluted tubule
70
What deficit is present in Liddle's syndrome?
Mutation of the ß-subunit of ENaC, making it constitutively active & causing excessive Na+ retention
71
At what bladder volume do people typically experience the urge to void?
~400mL
72
Regarding brainstem regulation of voiding reflex, which areas are facilitatory & inhibitory?
Facilitatory - pontine, posterior hypothalamus
Inhibitory - midbrain
73
Vasopressin ADH) receptors are in which class?
G-protein coupled receptors
74
Alcohol (decreases/ increases) vasopressin secretion
Decreases
75
The (low/ high) pressure receptors are the primary mediators f volume effects on vasopressin secretion
Low
76
___ is the most important determinant of ECF volume
Na+
77
True or false: renin is a glycoprotein and aspartyl protease
True
78
Angiotensinogen levels are increased by _____
Glucocorticoids, oestrogen, thyroid hormones, cytokines and angiotensin II
79
ACE is responsible for which major 2 enzymatic processes?
Conversion of angiotensin I -> II
Inactivation of bradykinin
80
(Angiotensin II vs noradrenaline) has more potent vasoconstriction action
Angiotensin II
81
True or false: angiotensin II penetrates the blood-brain barrier
False
It acts on the circumventricular organs instead
82
EPO has a half life of ___ and the principal site of inactivation is the ____
5hrs
Liver
83
EPO is predominately produced in which 2 organs?
Kidney (85%) & liver (15%)
Also some production in the brain, uterus & oviducts
84
The seminal vesicles produce ~____% of seminal fluid
60-70%
85
Which 3 hormones are produced by the corpus luteum?
Oestrogen, inhibin, progesterone
86
Which hormone is primarily responsible for ovulation?
LH (peak ~day 14 in response to 'critical level' of oestrogen)
87
During the luteal phase of the menstrual cycle, progesterone inhibits ___ and inhibin inhibits ___
Progesterone - GnRH
Inhibin - FSH
(negative feedback mechanisms)
88
Regarding breast enlargement / development during pregnancy: oestrogen is important for ___ growth, progesterone for ___ growth
Oestrogen - ductal growth
Progesterone - lobule growth
89
The nicotinic ACh-R activates ___ whereas the muscarinic ACh-R activates ___
Nicotinic - cation channel (Na+, K+)
Muscarinic - GPCR (Gi -> AC; Gq -> PLC)
90
Sweat glands contain which type of ACh receptors?
Muscarinic
91
Sympathetic pre-ganglionic fibres synapse with ___ cells in the adrenal ___
Chromaffin cells
Adrenal medulla
92
Alpha 2-ARs are mostly (pre/post) synaptic and inhibit release of ____
Pre-synaptic
Noradrenaline
93
ß2-ARs trigger skeletal muscle vaso____
Vasodilation
94
What are the 3 types of neurotransmitters and examples of each?
1) Amino acid derivatives: glutamate, aspartate (excitatory), GABA, glycine (inhibitory)
2) Peptides: vasopressin, somatostatin, neurotensin
3) Monoamines: NA, DA, 5-HT
95
Compare NMDA & GABA-Rs
NMDA - Na+ channel, excitatory; binds glutamate, glycine (allosteric modulator)
GABA - Cl+ channel, inhibitory; binds GABA, BZDs, barbiturates, EtOH
96
How many pairs of spinal nerves are there?
31
97
The Pre-ganglionic cell bodies of PNS/ SNS are located in the ____ of spinal cord
Intermediolateral column (IML)
98
Neurons in the _____ (nucleus) innervate the SA & AV nodes
Nucleus ambiguus
99
What is the daily caloric intake requirement?
2000 kcal/day for basal needs + 500-2500 kcal/day to meet energy demands
100
___ is the proenzyme of pepsin and is activated by ___
Pepsinogen
Gastric acid
Pepsin has optimal action in pH 1.6-3.2, and therefore does not function when gastric contents are mixed with alkaline pancreatic juices
101
__-__% of ingested calcium is absorbed
30-80%
102
Which form of iron is absorbable and which binds to transferrin?
Ferrous (Fe2+) form is absorbable (this is not the common form of dietary iron)
Ferric (Fe3+) binds to transferrin
103
Regarding renal blood flow, list a chemical that a) causes vasoconstriction, b) vasodilation and c) increases cortical flow but decreases medullary flow
a) noradrenaline (affects interlobular artery/ afferent arteriole) OR angiotensin II (afferent & efferent arteriolar vasoconstriction)
b) dopamine and ACh
c) prostaglandins
104
What are the 2 types of diuresis (renal) and give an example
Osmotic (non-absorbable filtrate retains water in lumen) e.g. hyperglycaemia
Water (decreases ADH & plasma osmolality) e.g. high volume H2O intake
105
Compare the action of aldosterone & ADH
Aldosterone - increases number of ENaC in collecting ducts, increasing Na+ (and thus H2O) reabsorption
ADH - increases expression of aquaporin 2 in collecting duct
106
List 3 hormones that cause Na/H2O retention and 3 that cause natriuresis
Retention
- Aldosterone
- ADH
- Angiotensin II
Natriuresis
- ANP
- PGE2
- Ouabain
107
What type of diuretics can cause hypokalaemia?
Loop & thiazide
108
Alcohol with ____ (increase/ decrease) ADH levels
Decrease
109
What is the RAAS sequence (include location of action & enzymes)
(liver produces) angiotensinogen -> (via renin) angiotensin I -> (via ACE in lung) angiotensin II -> (acts on adrenal cortex) aldosterone
110
What types of proteins are ACE and EPO, respectively?
ACE - dipeptidyl carboxypeptidase
EPO - glycoprotein
111
Prostacyclin is produced by ____ and causes vaso____, _____ and (promotes/ inhibits) platelet aggregation.
Thromboxane A2 is produced by ____ and causes vaso___ and (promotes/ inhibits) platelet aggregation
Prostacyclin (PGI2) - Vascular endothelium and smooth muscle cells in the blood
It causes vasodilation and renin activation (direct via JGA or indirect via reduced BP) and INHIBITS platelet aggregation
TXA2 - platelets; vasoconstriction, PROMOTES platelet aggregation
112
Group these substances into vasoconstrictors & vasodilators:
- lactate
- prostacyclin
- TXA2
- histamine
- platelet serotonin
- AVP
- ANP
- Endothelin-1
Vasoconstriction:
- TXA2
- platelet serotonin
- Endothelin 1
- AVP
Vasodilation:
- lactate
- prostacyclin
- histamine
- ANP
113
Endothelin-1 is a potent vaso____, acting more on (veins/ arterioles)
vasoconstrictor
Veins > arterioles
(It also has a particular effect on coronary artery vasoconstriction)
114
Sympathectomy will cause vaso_____
Dilation
115
What are the 4 locations of baroreceptors, and what does each monitor?
(1&2) Carotid sinus & aortic arch → monitor arterial circulation
(3) RA wall → monitor venous return
(4) LA wall → monitor pulmonary circulation
116
What is the O2 extraction rate in the coronary circulation at rest and during exercise?
Rest - 70%
Exercise - 100%
117
Noradrenaline overall acts to cause vaso___ of the coronary arterioles
Vasodilation
Acts on both alpha-ARs (constriction) and ß-ARs (dilation), but also causes increased HR, CO & SBP, triggering release of other vasodilator metabolites
(Note: if patient ß-blocked, will only act on alpha-ARs and cause life-threatening vasoconstriction)
118
What 5 factors regulate cerebral blood flow?
(1) Mean venous & (2) arterial pressures
(3) ICP
(4) Local cerebral vasoconstriction/ dilation
(5) Blood viscosity
119
_____ metabolism always remains constant regardless of blood flow
Cerebral
120
What is the percentage of oxygenated blood along the route for fetal blood flow ?
80% in umbilical vein -> 67% in IVC via ductus venosus -> 65% in LA -> 65% to brain / 60% trunk/lower body (further 'diluted' by deoxy blood from RV shunted via ductus arteriosus)
Portal/ systemic venous blood ~26%
121
Where are the SA and AV nodes located respectively?
SA - RA wall below SVC opening
AV - posterior interatrial septum, behind tricuspid valve
122
What are the average volumes for EDV, SV, ESV & EF
EDV = 130mL
SV = 70-90mL
ESV = EDS - SV = ~50mL
EF = SV/EDV = ~65%
123
Increased contractility shifts the Frank Starling curve ___
Up & Left
124
____ is the most potent vasoconstrictor
Angiotensin II
125
Dopamine acts on which receptors? (broad classes)
Alpha & ß1/ß2 adrenergic + dopaminergic
126
90% of re-entry circuits in atrial flutter are ____ (direction)
Anticlockwise
127
Oxygen vaso____ the pulmonary vascular tree via ___
Vasodilates via NO
128
Prostaglandins cause vaso____ of the ductus arteriosus
Vasodilation
Therefore withdrawal of PGs is needed for the ductus to close (together with increased bradykinin from the lung)
129
What is the threshold potential of cardiac pacemaker cells?
-40mV
130
What is the resting potential of ventricular myocytes?
-85mV
131
The AV node delays transmission of action potential by ____
0.1s
(Slows impulse to ~0.05m/s)
132
According to the law of Laplace, a dilated ventricle needs ____ (greater/ less) tension to overcome a given pressure
Greater
T = Pr/w, where T = tension, P = transmural P, r = radius, w = wall thickness
Dilated ventricle = wider radius
Another way to arrange equation for application to alveolus is P = (2 x wall thickness x surface tension)/radius
133
Phenylephrine is a(n) ______ agonist. It (increases/ decreases)
Alpha-adrenergic agonist
It increases TPR & BP
134
The rate of gas exchange is dependent on which 3 main variables?
Surface area
Membrane thickness
Diffusion coefficient
135
Only _____% of O2 dissolved in blood - the rest is carried on Hb
1.5%
136
Haemoglobin/ O2 displays _____ allosteric binding
Positive
137
The Bohr effect states that the affinity of Hb for O2 is _____ in the presence of CO2/H+
Reduced
138
CO2 is mostly transported as ___ in the blood
HCO3- (~90% of arterial CO2; ~70% of this enters plasma)
- Arterial: other 5% CO2 dissolved in plasma, 5% as carbamino compounds
- Venous: 60% HCO3-, 30% carbamino compounds, 10% dissolved
*CO2 + H2O -> (carbonic anhydrase) H+ + HCO3-*
139
What are normal tidal & residual volumes?
Tidal - 500mL (5-7mL/kg)
Residual - 1200mL
140
What is vital capacity (lung volumes)?
The expiratory + inspiratory reserve volume (maximum breathing capacity: everything except the residual volume)
141
Which measure of lung volumes is a good indicator of emphysema?
Functional residual capacity
142
Which muscles are responsible for active expiration?
Internal intercostals + anterior abdominal muscles
*Compared to quiet/ normal expiration, which is passive recoil of the chest wall*
143
Surfactant is produced by ______
Type II pneumocytes
144
In the pulmonary circulation hypoxia causes vaso_____ and in the systemic circulation it causes vaso_____
Pulmonary - vasoconstriction
Systemic - vasodilation
The same is true for hypercapnia
145
What is respiratory minute volume?
Tidal volume x resp rate
146
What is the basal consumption rate of O2 and production rate of CO2?
O2 - 250mL/min consumed
CO2 - 200mL/min produced
147
The ____ configuration of Hb has decreased affinity for O2 binding
'T' (tense) configuration
*Compare to 'R' (relaxed) configuration - increased affinity*
148
Carbonic anhydrase is present in RBC or plasma?
RBC
Rapidly converts CO2 + H2O -> H2CO3
149
Administration of 100% O2 has (MORE/LESS) effect on PaO2 as shunt fraction increases because ____
Less
Only improves shunted alveoli
Hb already fully saturated in adequate ventilated alveoli
150
What are the features of Virchow's triad?
1 - vessel wall injury
2 - altered blood flow (stasis)
3 - hypercoagulability
151
Clopidogrel (irreversibly/ reversibly) and ticagrelor (irreversibly/ reversibly) inhibit ____
Clopidogrel irreversibly; ticagrelor reversibly inhibit P2Y12
152
___ are the most abundant white blood cell line in the blood
Granulocytes (polymorphonuclear leukocytes)
153
In platelets, ADP, serotonin and calcium are found in ___ granules, whilst P-selectin, fibrinogen and PDGF are found in ____ granules
Dense delta 𝛅 granules
Alpha 𝛂 granules
154
What is the co-stimulatory signal?
CD4-R binds MHCII + CD28 (T cell) binds CD80/B7 (APC)
155
An ____ environment is needed to calcify bone, whereas an ____ environment is needed to break it down (acidic/alkaline)
Alkaline
Acidic
156
True or false: bile acids are amphipathic
True
They have both hydrophobic & hydrophilic parts
157
___ gallstones are radiolucent, whereas ___ gallstones are radio-opaque
Cholesterol - radiolucent
Calcium bilirubinate - radio-opaque
158
The renal blood flow is ~___% of cardiac output
25%
1.2-1.3L/min
159
The glomerular endothelium permits passive passage of _____ substances (3 features). The pores are approximately what size?
Neutral, cationic, up to 4nm
70-90nm
160
The juxtaglomerular apparatus is made up of ____ cells in the ___, and ___ cells in the ____
Granular cells in the afferent arteriole
Macula densa cells in the distal thick ascending loop of Henle and proximal DCT
161
In the collecting duct of the renal tubule, there are more ___ cells than ___ cells
P (principal) cells [Na reabsorption] > I (intercalated) cells [acid secretion]
162
True or false: The ascending loop of Henle is permeable to water
False
It is impermeable (both thin & thick portions)
The descending loop is permeable to water and responsible for concentration of filtrate
Thin ascending - permeable to ions
Thick ascending - active transport of ions
163
The respiratory system is a (HIGH/LOW) pressure & resistance system
Low
Pulmonary artery pressure ~25/10mmHg
164
Wherea re the J receptors located in the pulmonary system?
The pulmonary interstitium
165
Androgen & thyroid hormones (INCREASE/DECREASE) the levels of 2,3-DPG
Increase
166
Which hormones are secreted in the posterior pituitary? They are made in the ____ (specific)
ADH & oxytocin
Made in hypothalamus, in the supra-optic & paraventricular nuclei
167
Which hormones are made/ secreted in the anterior pituitary?
ACTH, PRL, FSH, LH, GH, TSH
168
What percentage of thyroid hormones are protein bound, and to which proteins
70% thyroxin-binding protein (TBG)
15% albumin
10% transthyretin (TTR)
169
What is resting neuronal membrane potential, and which ion is the main determinant?
-70mV
K+
170
Ouabain (promotes/ inhibits) the Na-K-ATPase
Inhibits
171
Melaena will be seen macroscopically when ≥____mL blood are lost daily in the stool
≥100mL
