Renal, Reproductive, Endocrine Physl Flashcards
1
Q
5 functions of the kidneys?
A
Regulate blood pressure and volume Maintain acid-base balance Excrete waste Gluconeogensis Secrete various hormones
2
Q
Waste products excreted by kidneys?
A
Urea, uric acid, bilirubin, creatinine
3
Q
3 hormones secreted by the kidneys?
A
Erythropoetin
Renin
1,25-dihydroxyvitamin D
4
Q
Which fluid do the kidneys regulate? What are the components of it?
A
Extracellular fluid: plasma, ISF, CSF
5
Q
Proportion of body’s intracellular to extracellular fluid
A
40% intracellular, 20% extracellular (total 60% of body weight is water)
6
Q
Relative Na, K, Cl, bicarbonate, phosphate concentrations in ECF vs ICF
A
Na, Cl and bicarbonate have higher concentrations in ECF
K and phosphate..ICF
7
Q
Aquaporins
A
Water channels in the plasma membrane, allowing for rapid diffusion of water
8
Q
What does the water concentration of a solution depend on?
A
The number of solute particles in that solution
9
Q
Osmolarity
A
The number of solutes per volume of solution,expressed in moles per litre
10
Q
A region with lower osmolarity has a higher or lower water concentration?
A
Higher water concentration
11
Q
Diffusion
A
Solute particles move from an area of higher concentration to an area of lower concentration
12
Q
Diffusion is due to what?
A
Random thermal motion
13
Q
Osmosis
A
Net diffusion of water across a semi permeable membrane from a region of high water concentration to a region of low water concentration
14
Q
Semi-permeable membrane
A
Allows water to cross, not any solutes
15
Q
Osmotic pressure & why it is important in cells?
A
Opposing pressure required to stop osmosis completely. It will stop water from flowing into the cell, and prevent the cell from bursting
16
Q
Tonicity
A
Determined by the concentration of non-penetrating solutes of an extracellular solution
17
Q
Non-penetrating solutes
A
Solutes that do not enter the cell
18
Q
Isotonic
A
Intracellular and extracellular solute concentrations(osmolarity) and water concentrations are the same. No net movement of water
19
Q
Hypertonic
A
Extracellular environment has a higher solute concentration (osmolarity) than intracellular environment. Water moves out of the cell
20
Q
Hypotonic
A
Intracellular environment has a higher solute concentration (osmolarity) than extracellular environment. Water moves into cell.
21
Q
Movement of fluid in absoption
A
Fluid moves from ISF to plasma
22
Q
Movement of fluid in filtration
A
Fluid moves from plasma to ISF
23
Q
Capillary hydrostatic pressure
A
Pressure exerted by fluid against capillary wall causing some of the fluid to move into ISF
24
Q
Interstitial fluid hydrostatic pressure
A
Pressure of ISF on the walls of the capillary, causing movement of fluid into capillaries
25
How do plasma proteins in plasma affect osmotic force?
A lot of plasma proteins in plasma means lower water concentration inside capillary compared to outside, so water tends to be pulled into capillary.
26
How do plasma proteins in ISF affect osmotic force?
Fluid will tend to be drawn into ISF
27
Starling forces
The 4 forces (Sum of the 2 outgoing forces minus the 2 ingoing forces) that determines the net filtration pressure
28
Which end has higher absorption/filtration? Why?
Venous end has more more absorption. Net filtration pressure is negative so fluid moves into capillary.
Arterial end has more filtration. Net filtration pressure is positive so fluid moves out of capillary.
29
Hilum
Inner concave part of kidney
30
Ureters
Drain urine from kidneys to bladder
31
Bladder
Sac that stores urine
32
Micturation
Releasing urine outside the body; urination
33
2 regions of the kidney
Outer: cortex
Inner: medulla
34
Nephron
Functional unit of the kidney. Urine is made here
35
Renal corpuscle and structure
Bulb-like structure with loops of capillaries
| Composed of the glomerulus and Bowman's capsule
36
Renal tubule segments
Proximal convolutes tubule
Loop of Henle
Distal convoluted tubule
Collecting ducts
37
Function of renal corpuscle
Initial filtering of blood
38
Podocytes
Cells which come in contact with glomelular capillaries; have foot-like processes
39
Development of renal corpuscle
Nephron develops as a tube that has no opening
Tubule invaginates and basal lamina is trapped between epithelial cells and epithelial layer
Epithelial cell layer differenciates into parietal and visceral layers
Outer layer does not fuse with inner layer, space left between them
Parietal layer flattens into wall of Bowman's capsule and visceral layer becomes podocyte cell layer
40
Parietal vs visceral layer
Parietal- outer layer of epithelial cells
| Visceral- layer closest to glomelular capillaries; podocytes
41
Fenestration importance?
Allows for filtration
42
Basement membrane
Gel like mesh structure composed of collagen proteins and glycoproteins
43
Purpose of foot preojections
Wrap around capillaries and leave slits in them, allowing for greater SA for filtration
44
2 types of nephrons
Cortical and juxtamedullary
45
What parts are found in the cortex?
Tubule segment, collecting duct, DCT, PCT
46
What parts are found in the medulla?
Loops of henle, ascending limb, renal corpuscles
47
Difference between cortical and juxtamedullary nephrons
They both perform filtration,absorption and secretion but the juxtamedullary nephrons additionally create osmotic gradients to regulate the concentration of urine.
48
Afferent arteriole
Brings blood into glomerular capillary network
49
Efferent arteriole
Blood exits glomerulus through it
50
Peritubular capillaries
Found around the PCT. They fuse together to form renal vein
51
Vasa recta
Capillaries found mostly associated with the juxtamedullary nephrons in medulla
52
Steps in urinary production
Glomerular filtration
Tubular absorption
Tubular secretion
Urinary excretion
53
Glomerular filtration
Fluid in blood is filtered across capillaries of glomerulus and into Bowmans capsule
54
Tubular reabsorption
Movement of a substance from tubule to blood
55
Tubular secretion
Movement of non-filtered substances from capillaries to tubular lumen
56
Urinary excretion
Blood is filtered at glumeruli and urine excreted from body
57
What can move from glomerular capillaries to Bowmans capsule? What cannot?
Water, electrolytes, glucose, waste products.
| Plasma proteins and blood cells cannot
58
Ultrafiltrate
Cell free fluid that has come into Bowman's space. Contains mostly all the substances at the same concentrations as in the plasma and in the filtrate.
59
Proteinuria
Proteins that weren't supposed to pass through filtration barrier end up in the filtrate and urine.
60
Glomerular capillary hydrostatic pressure
Hydrostatic pressure of the blood found in glomerular capillaries. Pushes fluid into Bowman's space
61
Bowman's space hydrostatic pressure
Hydrostatic pressure of fluid in Bowman's space. Pushes fluid in glomerular capillaries
62
Osmotic force due to proteins in the plasma
Due to plasma proteins; there is high solute concentration in capillaries due to presence of these proteins and less water, so this causes movement of fluid from Bowman's capsule to capillaries (water follows solute)
63
Which forces oppose and favour filtration?
Glomerular capillary hydrostatic pressure favours filtration.
Bowmans space hydrostatic pressure and osmotic force due to proteins in plasma oppose filtration.
64
How to determine glomerular pressure
Sum of the 3 pressures subtracted
65
Net filtration is always...?
Positive
66
Which factor would contribute to increased glomerular filtration rate?
Increased blood pressure
67
Which factor would contribute to decreased glomerular filtration rate?
Increase in protein concentration in plasma
68
Fraction of volume entering glomerular capillaries that is filtered?
20%
69
Volume of fluid excreted?
<1%
70
Glomerular filtration rate? What are the numbers?
The volume of fluid filtered from the glomerulus into the Bowmans capsule per unit time.
125mL/min or 180L/day
71
Factors affecting GFR?
Blood pressure
Neural and endocrine control
Permeability of corpuscular membrane
Surface area available for filtration
72
Autoregulation
Allows GFR to remain relatively constant despite large changes in arterial pressure
73
Autoregulation is regulated by changes in what?
Myogenic reflex and tubuloglomerular effect
74
Effect of constriction of afferent arteriole on GFR?
Decreased glomerular capillary hydrostatic pressure, therefore decreased filtration rate
75
Effect of constriction of efferent arteriole on GFR?
Volume of blood builds up in glomerular capillaries so increased hydrostatic pressure and increased filtration rate
76
Effect of dilation of efferent arteriole on GFR?
Decreased glomerular capillary hydrostatic pressure, decreased rate of filtration
77
Effect of dilation of afferent arteriole on GFR?
Increased blood flow, increased hydrostatic pressure increased filtration rate
78
Mechanisms which change arteriolar resistance?
```
Myogenic responses (muscle contracting/relaxing due to changes in pressure)
Hormones/neurotransmitters
Tubular glomerular feedback (controls the autoregulatory processes and affect GFR)
```
79
Juxtaglomerular apparatus
Specialized structure formed by the distal convoluted tubule and glomerular afferent arteriole
Next to the glomerulus
80
3 cell types that regulate GFR
Macula densa
Juxtaglomerular cells
Mesangial cells
81
Macula densa
Cells on the wall of distal tubule where the ascending limb is beggining to form the distal tubule.
Change afferent arterial resistance by paracrine effects. (adenosine)
82
What do macula densa sense?
Increase Na load and increased fluid flow through distal tubule
83
What do macula densa secrete?
Vasoactive compounds
84
Juxtaglomerular cells
Sit on top of afferent arteriole
85
Juxtaglomerular cells release what?
Renin, which controls afferent arteriole resistance
86
Juxtaglomerular cells are innervated by?
Sympathetic nerve fibers
87
Mesangial cells
Found in the triangular portion between afferent and efferent neurons. Allow podocytes to contract, and control filtration surface area.
88
Which cells are NOT considered as part of the JGA?
Mesangial cells
89
Tubuloglomerular feedback mechanism
Increase in GFR
Increase in flow
Flow past macula densa increases
Paracrine factors secreted from macula densa and act on afferent arteriole
Afferent arteriole constricts and resistance increases
Glomerular hydrostatic pressure drops
GFR decreases
90
Filtered load and how to calculate it
Amount of substance filtered by kidneys per day; how much load is filtered into Bowmans capsule
GFR x concentration of the substance in plasma
91
If substance excreted in urine is less than filtered load, what occured?
Reabsorption
92
Is substance excreted in urine is more than filtered load, what occured?
Secretion
93
What happens when a substance is filtered and secreted?
20% of substance filtered at Bowman's space, 80% moves in peritubular capillaries. As that small amount was being filtered, most of the substance ended up being secreted into urine. Body did not absorb any of substance.
94
What happens when a substance is filtered and partially reabsorbed?
20% of substance filtered at Bowman's space, 80% moves in peritubular capillaries. As that small amount was being filtered, the some was also being reabsorbed back into peritubular capillaries.
95
What happens when a substance is filtered and completely reabsorbed?
20% of substance filtered at Bowman's space, 80% moves in peritubular capillaries. As that small amount was being filtered, all of it ended up being reabsorbed by the peritubular capillaries. NONE was excreted in urine.
96
Inulin
Polysaccharide found in plants
97
Inulin renal handling
Filtered ONLY. Excreted completely in urine so no secretion or reabsorption
98
Creatinine renal handling
Filtered for the most part
99
Electrolytes renal handling
Filtered and partially reabsorbed
100
Glucose and amino acids renal handling
Filtered and completely reabsorbed
101
Organic acids and bases renal handling
Substance completely secreted into urine
102
PAH
Organic acid that undergoes filtration and secretion
| Measures renal plasma flow
103
How much % of water is reabsorbed?
99%
104
How much % of Na is reabsorbed?
99.5%
105
How much % of glucose is reabsorbed?
100%
106
How much % of urea is reabsorbed?
44%
107
How is glucose vs water and Na reabsorption regulated?
Glucose is not physiologically regulated while the body regulates the reabsorption of water and Na
108
2 pathways of reabsorption
Diffusion and mediated transport (major component involving transporters)
109
Transepithelial transport and its pathway
Substance will move from the tubular lumen to the interstitial space and into peritubular capillaries.
110
How does Na move across luminal surface?
Passively down conc gradient
111
How does Na move out of the cell across basolateral membrane?
Active transport using ATPase
112
How does Na move into peritubular capillaries?
Bulk flow
113
Reabsorption of Na by mediated transport
On basolateral membrane: transport of Na mediated by Na/K pump
On apical membrane: influx of Na caused by diffusion into the cell which has lower conc of NA
114
Clearance of zero
Refers to NO glucose present in urine because all filtered glucose is reabsorbed
115
In the proximal tubule glucose is reabsorbed by?
Active transport on luminal side by SGLT
| Facilitated diffusion on basolateral side using GLUT
116
Glucosuria
Above renal threshold glucose appears in urine
117
How does SGLT work?
Uses the inwardly directed Na gradient as "energy" to move glucose into cell from a low to high concentration. This is secondary active transport
118
Glucose crosses basolateral membrane using what?
GLUT
119
Relationship between plasma glucose concentration and filtration rate of glucose?
Linear relationship; proprotional. When plasma glucose concentration increases, filtration rate increases also
120
Relationship between plasma glucose and reabsorption of substance?
Initially linear, until 300mg/100mL plasma. Then the graph plateaus because it hit the transport maximum. No more glucose can be reabsorbed.
121
Transport maximum. What does it cause on graph?
All SLGT proteins that transport glucose from lumen to peritubular capillaries are saturated. Binding sites are all occupied therefore no more glucose can be absorbed, resulting in plateau on graph.
122
Relationship between plasma glucose and excretion rate of glucose?
Normally glucose should not be found in urine. Only happens if the body's limit for handling glucose has been reached (at 300mg/mL)
So graph starts and is linear once it hits 300 on x axis, since this is the renal threshold
123
Renal threshold
300 mg/mL
| Beyond this value, glucose comes out in the urine; there is no more reabsorption of glucose
124
Diabetes mellitus and cause
Capacity to reabsorb glucose is normal, but filtered load is greatly increased and is beyond threshold level to reabsorb glucose by tubules.
SGLT functions normally
Has too much glucose in blood due to insulin not functioning properly
125
Renal glucosaria
Mutation of SGLT results in inability to transport glucose from luminal side to peritubular capillaries
126
Urea reabsorption is dependant on?
Water reabsorption
127
Tubular secretion movement
From peritubular capillaries to tubular lumen
128
Tubular secretion involved mostly what ions?
H and K
129
Renal clearance
Measures the volume of plasma from which a substance is completely removed from the kidney per unit time
Bascially how well the kidneys remove substances
130
Renal clearance formula
Concentration of substance in urine x volume of urine passed / Concentration of substance in plasma
131
What is used to measure clearance?
Inulin, since it is completely excreted and not at all reabsorbed nor secreted.
Measuring clearance of inulin will provide GFR
132
Why does creatinine slightly overestimate GFR?
Because it undergoes slight secretion
133
Relationship between clearance and GFR
If clearance is greater than GFR of 125, substance is being secreted.
If clearnace is less than GFR of 125, substance is being reabsorbed
134
Relationship between GFR and conc of plasma for substance X for creatinine
GFR is inversely proportional to the plasma concentration of the substance
135
Which ion is actively reabsorbed?
Na
136
Which ion is transorted passively when Na is pumped out?
Cl
137
Which ion is secreted into tubules by cells of the distal and collecting ducts?
K
138
PCT major function
Reabsorbs majority of water and non wastes
| Solute secretion except for K
139
Loop of Henle major function
Creates osmotic gradient in interstitial space
140
DCT major fucntion
Physiological control for water absorption
| Homeostatic mechanisms of fine control of water and solute to make urine
141
Sources of water gain
Ingested liquid
| Oxidation of food
142
Sources of water loss
Sweating
Skin and airways (insensible)
GI tract, urinary tract, menustration
143
Water reabsorption is dependant on?
Na reabsorption
144
Which hormone regulated water absobtion?
ADH aka. vasopressin
145
What does ADH regulate and where does it take place?
Regulates specific aquaporins to allow water absorption in the collecting ducts
146
Which part of nephron has NO water reabsorption?
Distal tubule
147
Which parts has ADH control of aquaporins?
Large distal tubule and collecting ducts
148
Descending vs ascending limbs water reabsorption
Ascending limb has NO water reabsorption while descending does.
149
Goal of environment of interstitial space?
To generate a hyperosmotic environment on the outside of the tubules (interstitial space)
150
Where does active transport of NaCl occur?
Ascending limb
151
Net result of ascending limb active transport and no water movement?
Creates a gradient difference between interstitial fluid and ascending limb. NaCl is allowed to accumulate in interstitial fluid without water moving into it since ascending limb is impermeable to water
152
Net result of descending limb
Water keeps moving out until equilibrium is reached, and osmolarity in interstitial space and surroundings is the same.
153
Multiplication
As you move down the descending limb, the osmolarity increases, so the gradient is multiplied as fluid moves down the loop and at the very bottom it is very hyperosmolar
154
Why is counter current multiplier important?
To keep water in the body and produce a hypersmotic/concentrated urine
155
Osmolarity at the top of the ascending limb?
Low since NaCl can move out but water cannot
156
As water leaves collecting duct, osmolarity...?
Increases
157
What happens to water moving into interstitial space?
Juxtamedullary neurons create hyperosmolar gradient
158
Short vs long loops of Henle
Short- optimal for environments where lots of water does not need to be conserved
Long- optimal for environments where you need to conserve more water (hyperosmotic gradient is greater to conserve more water)
159
Vasa recta. Permeable to?
Blood vessels that run parallel to the loop of Henle. Permeable to both solutes and water
160
Counter current blood flow
Blood flows in through one direction and flows out the other
161
Why is a hyperosmotic interstitial gradient created?
To absorb water in the interstitial space
162
Purpose of vasa recta
Maintains the salt gradient at each level that the nephron tubules have created
163
How does the vasa recta help in countercurrent exchange?
Blood flow in vasa recta serves as countercurrent exchangers by helping maintain the Na Cl gradient. Vasa recta doesn't create any hyperosmolarity but maintains it because capillaries are freely permeable to ions, urea, water
164
What does the vasa recta maintain?
The gradient established by the Loop of Henle
165
How much percent of original amount of urea is excreted?
15%
166
Importance of minimal uptake of urea by vasa recta and recycling?
Helps in maintaining high osmolarity in medulla
167
Mechanisms used to maintain hyperosmotic environment of medulla?
Counter current anatomy and opposing fluid flow in loops of Henle
Reabsorption of NaCl in ascending limb
Impermeability of ascending limb to water
Trapping urea in medulla
Hairpin loops of vasa recta
168
Diuresis
Producing a large volume of urine
169
Antidiuresis
Reduction/supression of excreting a large amount of urine
170
What type of hormone is ADH?
Peptide hormone
171
What type of cells make ADH and where are they found?
Neurosecretory cells in hypothalamus. Found in the supraoptic nucleus.
172
AQP1
Water channels found in proximal convoluted tubule
173
AQP2,3,4
Water channels found in the collecting ducts
174
Which aquaporin types are regulated by ADH?
AQP2 is. AQP3 and 4 are not
175
ADH binds to receptor on cell, and through what mechanism are transcription factors activated and AQP2 regulated?
G protein coupled mechanism
176
Water moves across apical membrane through...?
AQP2
177
Water moves out basolateral membrane through...?
AQP3,4
178
What happens when there are low levels of ADH?
AQP2 channels are recycled by endocytosis
179
What happens in the absence of ADH?
Leads to diuresis because theres not enough AQP2 channels in luminal membrane of collecting duct so the cells are almost impermeable to water.
180
Diabetes insipidus
Large amounts of urine
181
Central diabetes insipidus
Failure to release ADH from posterior pituitary
182
Nephrogenic diabetes insipidus
Regular release of ADH but the hormone does not function properly. May be problem with the signalling pathway or cells within nephron
183
When ADH is increased...
AQP2 levels increase and more water is reabsorbed (pee less)
184
When ADH is decreased...
AQP2 levels decrease and more water is excreted (pee more)
185
Osmolarity gradient for dry/water deprived conditions?
Steep gradient, ADH will work to retain water
186
Osmolarity gradient for excess water conditions?
Not a steep gradient. More water is excreted in urine than absorbed
187
Water diuresis
Only water is excreted with no extra solutes in urine
188
Osmotic diuresis
Excess solute in urine is always associated with large amounts of water excretion
189
Na is never what? What happens instead?
Never secreted into renal tubules. It is EXCRETED
190
Low Na in plasma: short term regulation?
Baroreceptors regulate GFR
191
Low Na in plasma: long term regulation?
Aldosterone helps facilitate Na reabsorption
192
High Na in plasma regulation?
ANP regulates GFR and inhibits Na reabsorption.
| Also inhibits aldosterone actions
193
Baroreceptors
Used for short term regulation of low plasma volume (reflection of low Na levels)
194
Where are baroreceptors located?
Carotid sinus, aortic arch, major veins, intrarenal
195
How do baroreceptors work?
Sense changes in blood volume, peripheral resistance,
196
Where is baroreceptor info processed?
Medulla oblongata
197
Aldosterone
Steriod hormone that regulates Na reabsorption (acts to conserve it)
198
Aldosterone is secreted from?
Adrenal cortex
199
What triggers aldosterone release?
Low plasma volume due to low Na
200
Aldosterone site of action
Cells of the distal tubule and collecting ducts
201
How does Na in diet regulate aldosterone secretion?
High amounts of Na: low aldosterone secretion
| Low amounts of Na: high aldosterone secretion
202
Renin
Enzyme that senses low NaCl in blood.
| Converts angiotensinogen to angiotensin I
203
Angiotensin II
Sensor that senses secretion of aldosterone
204
Angiotensinogen to aldosterone pathway
Angiotensinogen to angiotensin I to angiotensin II (via ACE) and then angiotensin II acts upon adrenal cortex to stimulate release of aldosterone.
205
ACE inhibitor
Manages high BP by blocking ACE enzyme. Reduces plasma Na concentration by blocking angiotensin I to II conversion and ultimately blocking aldosterone release.
206
Most important trigger for release of aldosterone?
Renin-angiotensin mechanism
207
Renin-angiotensin mechaism initiated in reponse to..?
Sympathetic stimulation of renal nerves
Decreased filtrate osmlarity
Decreased BP
208
Juxtaglomerular cells
Mechanoreceptors on the wall of afferent arteriole.
Sense plasma volume
Secrete renin
209
Macula densa
Chemoreceptors on wall of DCT
| Sense NaCl load of filtrate
210
What do macula densa do when Na concentration decreases in the filtrate?
They sense it and release signalling molecules, which stimulate renin release by juxtaglomerular cells
211
3 factors affecting renin release?
Sympathetic input from extrarenal baroreceptors
Intrarenal baroreceptors
Signals from macula densa
212
ANP
Synthsized and secreted by cardiac atria.
| Important for regulating high levels of Na
213
Site of ANP action?
On cells of several tubular segments
214
What does ANP do?
Inhibits aldosterone, so inhibits Na reabsorption
| Increases GFR and Na excretion
215
What stimulates ANP secretion?
Increased Na concentration
Increased blood volume
Atrial distension
216
K concentration is regulated where?
Cortical collecting ducts
217
Hyperkalemia
Excessively high concentration of K in blood
218
K levels physiologically regulated by? How?
By aldosterone. When there is a high extracellular K concentration, aldosterone acts to increase secretion of K in urine.
219
ADH secretion is directly sensitive to what?
Extracellular K level
220
What can happen with pH changes? (4)
Changes in shape of proteins
Neuronal activity changes
K ion imbalances
Irregular cardiac beats
221
Volatile acid vs non volatile
Volatile acids can be converted into gases and then eliminated by exhaling
222
Volatile and non volatile acids produced in our body?
Volatile: CO2
Non: phosphoric and sulfuric acid
223
Sources of H gain?
Generation of H from CO2
From non volatile acids
Loss of bicarbonate in diarrhea
Loss of bicarbonate in urine
224
Sources of H loss?
Vomiting
In urine
Hyperventilation
225
Buffer
Substance that binds to H and forms a H buffer conjugate
| Weak acid+its conjugate base
226
Extracellular buffer example
Bicarbonate
227
Intracellular buffers examples
Phosphate ions
| Hemoglobin
228
Acid base balance formula
CO2+H2OH2CO3H + HCO3-
229
What happens when respiration rate is not high enough?
Passage of blood through peripheral tissues generate H
230
Which organ plays a short term role in pH regulation?
Lungs
231
Increased H conc causes what?
Stimulates ventilation
232
Decreased H conc causes what?
Inhibits ventilation
233
Which organ plays a long term role in pH regulation?
Kidneys
234
When one H ion is lost from body...what happens
One HCO3 is gained
235
Alkalosis. What happens after
Decrease of plasma H. Kidneys excrete more bbicarbonate
236
Acidosis. What happens after
Increase of plasma H.
| Kidneys make new bicarbonate and send it to blood
237
Reabsorption of HCO3: mechanism I
Extra H binds to intracellular buffer HPO4
HCO3 is still generated by tubular cells and diffuses into plasma
Net gain of HCO3
238
Reabsorption of HCO3: mechanism II
Only cells from proximal tubule are involveed
Uptake of glutamine
NH4 and HCO3 are formed
NH4 is actively secreted by counter transport into lumen
HCO3 is added to to plasma
239
Initial buffer and what happens when its depleted (acidosis)
Biacarbonate. Then phosphate and then glutamine metabolism
240
Respiratory acidosis caused by? How does kidney compensate?
Result of decreased ventilation. Increase blood PCO2.
| Kidney secretes H and lowers plasma H conc.
241
Respiratory alkalosis caused by? How does kidney compensate?
Result of hyperventilation. Decrease blood PCO2. High altitudes. Kidney excretes HCO3
242
Metabolic acidosis
Occurs in diarrhea, severe excersise. Results in increased ventilation and increased H secretion
243
Metabolic alkalosis
Occurs after prolonged vomiting
| Results in decreased ventilation and increased HCO3 excretion.
244
Functions of the reproductive system
Provides gametes for procreation
Mating
Fertilization
245
Function of gonads
Produce the gametes
246
What are the gonads of the male reproductive system?
Testis
247
Scrotal sac & what is contained in it?
Found outside the body. Contains testes, blood vessels, nerves
248
Importance of countercurrent blood flow?
Cools the blood before it enters testes. Heat from arterial blood is passed to cooler venous blood
249
Why are testes housed outside the body?
So that the temperature is maintained at least 2 degrees below core body temp. This is necessary for optimal spermatogenesis.
250
Spermatic cord
Passes through a slit in the abdomen down into scrotal sac.
| Combination of vas deferens, blood vessels, nerves
251
Testes during gestation period
Present in abdominal cavity at 8 weeks
252
Testes first phase of descending
During 8-12 weeks testes will move down towards inguinal canal
253
Second phase of testes descending
Between month 7-9 testes pass through inguinal canal and rest in the scrotum
254
Seminiferous tubules
Site of sperm production
| Contain a lumen and many spermatogenic cells
255
Mumps virus
Causes the lumen to become much bigger making the spermatogenic cells appear small. This affects spermatogenesis
256
Leydig cells/interstitial cells
Found in connective tissues surrounding seminiferous tubules.
Produce testosterone
257
Sertoli cells
Epithelial cells lining the circular seminiferous tubule
| Help in sperm development
258
Smooth muscle cells of testes
Muscle like
| Contractile properties which help move sperm forward
259
Tight junctions of testes
Do not let infections or anything that may harm sperm through
Create and invisible ring-like structure that is impermeable.
Helps in forming the blood-testis barrier
260
Sertoli cells: 11 functions
Support sperm development
Secrete luminal fluid for sperm housing
Secrete androgen binding protein under influence of FSH
Androgen buffer
Maintains androgen concentration in lumen
Target cells for testosterone and FSH
Secrete paracrine factors that stimulate spermatogenesis
Secrete inhibin
Negative feedback loops for FSH
Phagocytosis of old sperm
Site of immunosuppression (Blood testes barrier)
261
Testosterone and where is it produced?
Lipophilic, steroid hormone synthesized by cholesterol.
| Principally produced by the testes in males
262
Progesterone
Intermediary hormone synthesied from cholesterol. May be converted to mineralcorticoids, glucocorticoids, or androgens depending on enzymes present.
263
Action of testosterone?
Influences gene transcription and protein synthesis to produce response in target cell
264
DHT
Maintains sexual characteristics and tissues, like prostate gland and secondary male sex characteristics
265
How is testosterone converted into estrogen? Where does this happen?
By aromatase
| In the brain, testes, adipose tissue, liver
266
Plasma testosterone levels before birth
High peak of testosterone and then levels decrease until birth
267
Plasma testosterone levels after birth
Right after birth there is a peak but then levels decrease through childhood
268
Plasma testosterone levels from adolescence to adulthood
Slowly increase and remain high throughout adulthood.
| Slowly start declining around age 40
269
What is pulsatile secretion and why is it necessary?
Secretion of GnRH every 90 min causing the pulsatile release of hormones. Occurs at the onset of puberty in males.
Important because cells of the anterior pituitary will not respond to constant GnRH, only pulsatile.
270
High frequency pulses of GnRH results in predominant secretion of?
LH
271
Low frequency pulses of GnRH results in predominant secretion of?
FSH
272
LH
Acts on Leydig cells to stimulate testosterone secretion
273
How is testosterone a negative feedback regulator?
Decreases the amplitude of pulsatile secretion, which results in down regulation of receptors for GnRH so less release of LH
274
Effects of androgens (6)
Stimulate spermatogenesis
Promote development and maintenance of secondary sex characteristics
Increase sex drive
Proetin synthesis
Stimulate growth hormone secretion
Development of male reproductive structures
275
What happens in spermatogenesis when the spermatogonium undergoes mitosis?
One cell remains as a spermatagonium to prevent depletion.
| The other is called the primary spermatocyte and progresses on to become mature sperm
276
What happens to primary spermatocyte?
Meiosis occurs and produces 2 secondary spermatocytes from that one.
Chromosome number is halved
277
Each secondary spermatocyte gives rise to...?
2 spermatids, each with haploid number of chromosomes
278
Final sperm are called? How many are formed?
Spermatozoa. 4, each with haploid chromosomes
279
Where exactly does spermatogenesis occur in the sertoli cells?
From the basement membrane to the lumen, and occurs in the space between Sertoli cells
280
Spermiogenesis
Last stage in spermatogenesis where spermatids mature into motile spermatozoa by aquiring flagella and cytoplasm is shedded to make a sperm shape
281
Parts of sperm head
Nucleus
| Acrosome
282
Acrosome
Vesicle close to plasma membrane at tip of sperm head
| Contains enzymes needed for fertilization
283
Mid piece of sperm contains many..?
Mitochondria needs for movement of tail
284
Tail of sperm movement
Whip like movements
285
Where are sperm stored until ejaculation?
Vas deferens
286
3 male accessory glands
Seminal vesicles, prostate glands, bulbourethral gland
287
Seminal vesicles
Secrete alkaline fluid with enzymes, fructose, and prostaglandins
288
Why is the fluid secreted by semincal vesicles alkaline?
To neutralize the highly acidic environment of female genital tract
289
Prostaglandins function
To contract the female tract to to help sperm move forward
290
Prostate gland
Secretes enzymes like PSA, and citrate
291
PSA
Protease that breaks down proteins in the seminal clot making semen more fluid
PSA is also a biomarker for detection of abnormal growth of prostate tissue
292
Bulbourethral glands
Secrete viscous fluid with mucous
293
Male sexual response is controlled by?
ANS
294
Function of seminal fluid?
Dilution of sperm
295
Erection phase is mainly controlled by?
Parasympathetic nervous system
296
When the penile tissue is not erected (relaxed state) what is the dominant control?
Sympathetic nervous system
297
Emission phase is controlled by?
Sympathetic nervous system (thoracolumbar division)
| Muscle contraction to move sperm to mix with seminal fluid
298
Ejaculation phase is controlled by?
Somatic nervous system since its skeletal contraction
299
What happens during erection?
When parasympathetic nerve is stimulated, NO is released, stimulating production of cGMP
cGMP acts to dilate smooth muscle
cGMP is broken down by phosphodiesterase and erection ceases
300
How is erectile dysfunction treated?
Viagra, which acts as an inhibitor for phosphodiesteraase
301
Site of fertilization?
Fallopian tube
302
Site of sperm maturation?
Epididymis
303
Capacitation
Physiological maturation of sperm cell membranes before fertilization can occur.
304
Acrosomal reaction
Sperm must penetrate the zona pellucida of egg.
Acrosomal reaction is triggered by the binding of the sperm to zona pellucida, and pores are created so acrozomal enzymes can pass through and allow sperm to create a path through zp
305
Fertility in men vs women
In men: sperm are always fertile
| Women: only during ovulation
306
Female gonads
Ovaries
307
Uterine tubes
Transport ova from ovaries to uterus
| Contain hair like structures called fimbrae to help with movement
308
Movement of ovum through tube
Intially: peristaltic contractions
| And then mostly ciliary actions
309
Ectopic pregnancy
When cilia do not mvoe properly in ovi duct, resulting in fertilized egg in in uterine tube
310
Perimetrium
Outer layer of uterus
Epithelial cells, connecting tissues
Protective
311
Myometrium
Middle layer of uterus
| Muscular
312
Endometrium
Inner layer of uterus
Contains connective tissue and glycogen
Cyclic change every month
313
Cervix
Canal leading to vagina
314
Birth canal
Cervix and vagina
315
Follicles
Densely packed shells of cells containing an immature oocyte at all stages prior to ovulation
316
Ovary
Contains follicles in different stages of growth
317
Primidorial, primary, and mature follicles?
Primadorial- very small
Primary- medium
Mature- large, with a fluid filled cavity
318
Ovarian cycle
Development of ovarian follicle, rupture, and degeneration
319
Uterine cycle
Menstral cycle
| Essentially preparing endometrium for possible embroyo in case of fertilization
320
Hormonal cycle
Controlled by FSH and LH, causing ovarian changes during monthly cycle
321
Ovarian cycle phases
```
Follicular phase:
First 14 days
Development of follicles
Ovulation:
On 14th day
Luteal phase:
Next 14 days
Egg is released
```
322
Uterine cycle phases
Mentrual phase:
Bleeding, shdding of endometrial layer for about 5 days
Proliferative phase:
Layers of endometrium widen
Functional layer of endometrium develops
Secretory phase:
Further vascularization and development of uterine glands
323
Which phases coincide?
Menstrual and proliferative phases of uterine cycle coincide with follicular phase of ovarian cycle.
Secretory phase coincides with luteal phase of ovarian.
324
Oogenesis
Development of female gamete
325
Primidorial follicles
Single oocyte surrounded by a single layer of epithelial cells
326
How does follicle grow?
By mitosis of granular cells
327
Primary follicle stage
Growth stage
| Grnaular cells secrete proteins and glycopreoteins which forms a thick layer around the oocyte (zona pellucida)
328
Preantral follicle
Mitosis of granula reult in many layers around oocyte
Early theca cells develop
No antrum
329
Early antral follicle
Fluid filled spce in antrum begins to fill
330
Mature follicles
Major growth due to growth of antral space
| Cumulus oophorus
331
Corpus albicans
Empty structure which functions as temporary endocrine structure. Eventually dissapates
332
Which follicles become the dominant ones?
The one that secretes the highest amount of estrogen
333
Hormonal cycle phases
Estrogenic phase: first 14 days
Predominant hormone is estrogen
Progestational phase: after ovulation
Prodominant hormone is progesterone
334
FSH effect on granular cells
Increases rate of mitosis
335
Zona pellucida
Seperates the oocyte from the inner layer of granulosa cells
336
2 cell compartment theory
LH acts on its receptors in theca cells and androgens are secreted
Theca cells convert cholesterol to progesterone to androgens
Inside the granulosa cells, androgens are converted to estrogen
337
How does FSH help with making estrogen?
Stimulates aromatase production, which helps convert androgens to estrogen in granulosa cells
338
Granulosa cells secrete...?
```
Antral fluid
Paracrine factors
Inhibin
Estrogen
Substance that forms zona pellucida
```
339
Estrogen and feedback in the axis
Negative feedback- estrogen can dampen the amplitde of pulse generator or reduce responsiveness of pituitary to GnRH
Positive feedback- estrogen can act on hypothalamus to increase amplitude of pulse generator or increase responsveness
340
Progesterone and feedback in the axis
Only has negative feedback- in the lack of estrogen it produces negative feedback on level of both the anterior pituitary and hypothalamus
341
When does the second meitotic division occur?
After ovulation and only if the secondary oocyte is fertilized by male gamete
342
Net result of oogenesis?
One primary oocyte with n number of chromosomes
343
Net result of spermatogensis?
4 spermatozoa with n number of chromosomes
344
Estrogen has an inhibitory effect on..? When?
Gonadotropin, when plasma concentrations of estrogen are low
345
During early proliferative stages what happens with estrogen levels?
Estrogen levels increase
346
Rapidly increasing estrogen causes sharp rise in?
LH, causing LH surge
347
Estrogen at high levels causes?
Positive feedback effect on gonadotropins
348
When is there a large increase in progesterone?
After the corpus luteum is formed
349
Where does the estrogen in LH surge come from?
As dominant follicles secrete more and more estrogen, , estrogen levels increase
350
Proliferative phase prepares for what?
Fertilized ovum
351
What happens during proliferative phase?
Endometrial lining grows and develops
Smooth muscle layer thickens
Mucus secreted from cervical glands
352
What happens during the secretory phase?
Blood supply increases
Glands enlarge and secrete glycogen-rich fluids
Cervical secretions are more sticky
353
Effects of estrogen on ovaries?
Increased growth of follicles
| Increased receptors for LH, FSH, estrogen, progesterone
354
Effects of progesterone on ovaries?
Decreased FSH induced estrogen production
| Decreased receptors for estrogen
355
Effects of estrogen on uterus?
Increased growth of endometrium and myometrium
Increased blood flow and contractibility
Increased sensitivity to oxytocin
356
Effects of progesterone on uterus?
Increased endometrial secretions
Decreased contractility
Decreased sensitivity to oxytocin
357
Effects of estrogen on breasts?
Increased duct growth, fat deposition, size of areola
358
Effects of progesterone on breasts?
Increased alveolar growth
359
Zygote
Fertilized egg cell resulting from the union of male and female gametes
360
Polyspermy
Multiple sperm fertilze one egg
361
Pronucleus
Pair of gametic nuclei before their fusion leads to a formation of a nucleus of the zygote
362
Morula
Made of many cells, and develops into blastocyst. Cells are totipotent at morula stage
363
Identical twins arise from?
Division of totipotent morula cells
364
Fraternal twins arise from?
Fertilization of 2 separate oocytes released during the same cycle
365
Blastocyst
Cells lose their totipotency and start to differenciate
| No zona pellucida
366
Outer cell layer of blastocyst will become?
Fetal placenta
367
Inner cell layer of blastocyst will become?
Embroyo
368
What happens when blastocyst enters uterine site?
Inner cell mass has lost its totipotency and will develop into embroyo
369
How does implantation occur?
Blastocyst will anchor itself to the wall of the endometrial lining
Sticky trophoblast cells anchor themselves the the endometrial lining
370
Trophoblast cells divide into what 2 parts?
Syncytiotrophoblast and cytotrophoblast layers
371
Syncytiotrophoblast layer
Outer trophoblast cells enter deep into the endometrial layer and start dividing and become fused. They form a syncytium (multiple nuclei but no cell membranes)
372
Cytotrophoblast layer
Trophoblast layer closest to the inner cell mass becomes cytotrophoblast layer. These cells release hormones for the growing embroyo
373
Decidual response
Response of the endometrial tissue where there is the appearance of blood vessels and glycogen secreting glands for the newly anchored embroyo or blastocyst/
374
Fetal placenta develops from?
Develops from the same blastocyst that forms the fetus
375
Maternal placenta develops from?
Maternal uterine placenta
376
Amnion
Innermost membrane that encloses the embroyo
377
Chorion
Embroyonic derived portion of placenta
378
Chorionic villi
Finger-like projections on chorion that allow for faster transfer of materials between maternal and fetal blood
379
Umbilical arteries
Carry deoxygenated blood from fetus to placenta
380
Umbilical veins
Carry oxygenated blood from placenta to fetus
381
Functions of the placenta
Temporary endocrine gland
Exchange tissue for gases, nutrients, waste
Filter/immunological barrier
382
hCG during pregnancy released from? Level during pregnancy? Function?
Released from chorionic part of placenta.
Initial peak at 2 mo, then decreases and stays low during pregnancy.
Helps maintain corpus luteum
383
hPL
Human placental lactogen
Anti-insulin like actions in mother, it allows plasma glucose levels to remain high, helping fetus take up more glucose through placenta
384
Progesterone during pregnancy
Once corpus luteum degenerates, prog is released
Decreases uterine contractions
Inhibits secretion of LH or FSH
Stimulates growth of alveolar ducts
385
Estrogen during pregnancy
Once corpus luteum degenerates, est is released
Causes growth of myometrium and mammary ducts
LH and FSH inhibited
386
Positive feedback loop of oxytocin release
During childbirth, pressure of fetus head against cervix causes oxytocin release via anterior pituitary
Oxytocin acts on myometrial layer, binding to the tissue and causing more contractions
387
Myometrial contractions are increased by...?
Oxytocin, prostaglandins, estrogen, stretch
388
Cervical ripening
Process that makes the cervix soft, allowing for easier expansion
389
Hormones influencing cervical ripening? how?
Relaxin and prostaglandins
| Relaxin relaxes the cervix while progesterone inhibits contractions if mother is not ready to deliver yet
390
Prolactin
Released from ant pit
| Stimulates production of milk/lactation
391
Lactogenesis
Cells in the breast tissue start making milk
392
Oxytocin role in lactation?
Needed for milk ejection/ let down
393
Galactapoesis
Maintenance of lactation while mother is breast feeding
394
Alveolar epithelial ducts
Synthesize milk but CANNOT release milk
395
Myoepithelial cells
Muscle like and have contractile properties to expel the milk
396
Myoepithelial cells have receptors for?
Oxytocin
397
Suckling process
Suckling stimulates mechanoreceptors (tactile receptors) in breast, signal sent to hypothalamus and oxytocin is released.Contraction occurs in myoepithelial cells of breast and milk is ejected.
398
Dopamine role in suckling
Inhibits prolactin secretion
399
2 Hormones that impose male characteristics?
Testosterone and AMH
400
SRY gene
Present in males because of the Y chromosome
| Allows testes to develop
401
Klinefelter syndrome
XXY
| Infertile
402
Turners syndrome
Lack of X chromosome
XO
Streaked ovaries (flattened)
403
Double genital duct system in males vs females
Wolffian ducts persist and Mullerian ducts regress in males
| Mullerian ducts persist and Wolffian ducts regress in females
404
MIH
Mullarian inhibiting hormone
| Hormone present in only males that causes Mullerian duct to regress
405
What causes development of the male internal genitalia?
Testosterone secreted from Leydig cells
406
Teststerone is converted to what?
DHT by 5 alpha reductase
407
What does DHT do?
Causes masculisation of male external genitalia
408
Congenital adrenal hyperplasia
Genetically female (XX) but phenotype is male
Caused by too much androgens produced in fetal stage
Decreased cortisol, so increased ATCH, so adrenal androgens, so increased mascularization
409
Androgen insensitivity disorder
```
Genetically male (XY) but phenotype is female
Tissues were unresponsive to testosterone during development so Wolffian ducts cant develop
Male internal and external genitalia do not develop
```
410
What triggers onset of puberty?
Increased secretion of GnRH causes more LH and FSH secreted
411
Kisspeptin
Neuropeptide that acts on the cells that release GnRH
412
Hormonal changes in menopause
Follicular depletion
Ovulation ceases eventually
Decreased estrogen and inhibin and progesterone
Increased FSH:LH ratio
413
Nervous system vs endocrine system
Nervous system is rapid and short term regulation while endocrine system is slower but more sustained control over long term processes
414
Exocrine glands
Glands that empty their secretions directly into body cavities or onto body surfaces via tubular ducts
415
Endocrine glands
Ductless system that release secretions directly into bloodstream
416
Endocrine signaling
Hormone released into bloodstream and acts on distant target sites
417
Nervous signalling
NT is released into synapse close to target site
418
Neuroendocrine signalling
Release secretions into a blood supply
419
Hormone characteristics
Regulate homeostasis
High potency
Actions are mediated through specific receptors
Delay of response
Secreted irregularily in phases
Most are carried in blood by binding proteins
420
Steroid hormones are derived from?
Cholesterol
421
Protein hormones include?
Amines
Peptides
Proteins
422
How does cholesterol enter the cell?
Bound to LDL
423
What happens once cholesterol is in the cell?
Moves to mitochondria to eventually form pregnenolone and and be further modified into different steriod molecules.
424
How is mRNA converted to a hormone?
mRNA, pre hormone, pro hormone, hormone
425
Secretory vesicle
Vessel that mediates transport of cargo like NTs or hormones
426
Secretory vesicle roles?
```
Protects hormone from degredation
Resevoir
Provides a transport mechanism along microtubules and microfilaments
Release mechanism (exocytosis)
Provide for quantal release
```
427
Roles of binding proteins?
Increase solubility and concentration of lipid soluble hormones
Increases size of hormone, protecting against degredation
Inactivates free hormones
428
Negative feedback in regulating hormone secretion
Inhibits hormone secretion when circulating levels are high and increases when they are low
429
Positive feedback in regulating hormone secretion
Rare, but there is a participation of negative feedback inhibitory signals that will terminate secretion rates
430
Requirement for hormonal action
Binding of a hormone to specific receptor
431
Nuclear receptors
Receptors located in nucleus
| Produce effects by altering protein synthesis
432
Cytoplasmic receptors
Receptor is found in intracellular transport
| Provide a resevoir of the hormone within target site
433
Protein hormones cannot cross the ...? What must they do?
Cant cross the cell membrane. They must bind to membrane bound receptors
434
Sensitization
Increase in affinity of a receptor
435
Down-regulation
Cells down-regulate receptors in response to high hormone concentrations in the blood
436
Up-regulation
Cells up-regulate receptors in response to low hormone concentrations in the blood
437
Defects in rate of hormone synthesis is due to?
Problems with endocrine gland
438
Defect in regulation of hormone is due to?
Problem in hormone action because hormone action requires feedback
439
Defect in hormone action is due to?
Problem with target tissue
440
Neurohypophosis/posterior pituitary
Down growth from the brain or hypothalamus
| Neural tissue
441
Anterior pituitary/adenohypophysis
Non neural tissue
| Results from invagination of roof of mouth
442
Intermediate lobe
Between the ant and post pituitary
443
Infundibulum
Contains the axons of neurons in the hypothalamus and blood vessels
444
Where is ADH produced?
Supraoptic nuclei
445
Where is oxytocin produced?
Paraventricular nuclei
446
Neurophysins
Transport ADH to neurosecretory granules or vesicles in the nerve
447
Main stimuli for ADH secretion
Decrease in blood volume
| Increase in blood osmolarity
448
ADH secretion increased by?
Stress, heat, nicotine, caffeine
449
ADH secretion decreased by?
Cold, alcohol
450
Hypothalamic diabetes insipidus/central DI
Problem of ADH production
451
Nephrogenic diabetes insipidus
Problem of ADH action
452
SIADH
Excess ADH due to problem of ADH production, feedback failure
453
Poluria
Large amounts of dilute urine
454
Polydipsia
Excessive fluid intake
455
Hyponatremia
Excess ADH and decreased aldosterone
456
Median eminence
Capillary bed which recieves axons from nuclei in the hypothalamus
457
Hypothalamal-hypophyseal portal vessels
Venous or portal blood vessels which run into the anterior pituitary
458
Short portal vessel
Blood vessel which comes from the capillary bed in the posterior pituitary
459
Parvocellular neurons
Have small cell bodies and short axons
| Produce neural secretions that are released into blood vessels down to anterior pituitary
460
Magnocellular neurons
Large neuroendocrine cells located in hypothalamus
| Synthesize ADH and oxytocin
461
GnRH
Stimulates release of FSH and LH
462
GHRH
Stimulates release of growth hormone(GH)
463
TRH
Stimulates release of TSH and prolactin
464
PRFs
Stimulate release of prolactin
465
CRH
Stimulate corticotropin release
466
SRIF
Inhibits release of GH and TSH
467
PIFs. Example?
Inhibit release of TSH and PRL
| Dopamine
468
TSH
Stimulates thyroid gland
| Secretes T3 and T4
469
ACTH
Stimulates adrenal cortex
| Secretes cortisol
470
Somatomedins
Induce growth effects on soft tissues and bone
471
How is GH release inhibited?
By Somatomedins
GH inhibits its own release
By products of lipolysis and glucose
472
How do certain meals affects GH release?
Meals high in glucose or fatty acids supress GH release
| Meals high in amino acids increase GH release
473
Dwarfism
Due to GH deficiency in juveniles.
474
Isolated growth hormone deficiency (Type I)
Defect in GH production
475
Laron type dwarfism
Defect in GH action due to problem with GH receptors
476
GH dwarfs vs thyroid dwarfs
GH dwarfs have normal body proportions just shorter in height, while thyroid dwarfs have body proprtions of an individual much younger than themselves
477
Somatopause
GH deficiency in adults.
Decrease in lean muscle tissue and increase in fat tissue.
Thymic atrophy
478
Acromegaly and symptoms
```
Excess GH in adults. Adult does not grow in height, but hands, bones of face, etc widen and enlarge
Protruding jaw
Hirsutism (hair growth excessive)
Due to GH secreting tumour
Enlarged breast tissue in males
```
479
What hormone inhibits prolactin secretion?
Progesterone
480
Hyperprolactenemia. How to treat it?
Excess prolactin resulting in decreased libido, amenorrhea, gonadal dysfunction
Dopamine agonist for treatment
481
Hypoprolactenemia
Deficiency in prolactin
| Gonadal dysfunnction and impairment of lactation
482
Pituitary diabetes
Excess of all anterior pituitary hormones
483
Hypopituitarism
Deficiency in pituitary hormone production
484
What do thyroid hormones do?
Increase metabolic rate and heat production
Enhance grwoth and CNS development
Enhance sympathetic activity
485
Glycoprotein hormones
Contain sugar residues
Made of alpha and beta subunit
Promote receptor recognition and prevent degredation
486
Basic unit of the thyroid gland?
Follicle
487
Thyroglobulin, where is it synthesized and secreted?
Precursor for thyroid hormone biosynthesis
Synthesized in the follicular cells of rough ER
Secreted into the colloid
Contains numerus tyrosine residues
488
The 2 thyroid hormones. Which is more active?
T3 (triiodothyrinine) and T4 (thyroxine)
| T3 more active
489
How is T4 a precursor hormone?
Degraded by deiodinase to T3 where iodine is lost from thyroxine
490
Monoiodotyrosine
Produced by addition of 1 iodine attached to tyrosine
| MIT
491
Diiodityrosine
Addition of 2 iodines attached to tyrosine (DIT)
492
Thyroid peroxidase
Responsible for attaching iodine to tyrosine on thyroglubulin, and for oxidizing iodides
493
DIT on TG+MIT=?
T3
494
DIT on TG+DIT=?
T4
495
Thyroid binding globulin
Binds both T3 and T4 to be carried into blood
496
Membrane bound receptors
Receptors that are linked to channels within the membrane
| Binding of the hormone to the receptor opens the channel allowing glucose to enter
497
Cytoplasmic receptors
Act as a resevoir of thyroid hormone in the target tissue
498
Nuclear receptors
Affect gene transcription and protein synthesis
499
Hyperthyroidism
Caused by excess T3 and T4, due to problem with thyroids gland, pituitary gland or hypothalamus
500
Primary problem caused by thyroid gland
Produces excess T3 and T4
| Toxic goiter
501
Secondary problem caused by pituitary gland
Increased TSH
| Goiter
502
Tertiary problem caused by hypothalamus
Increased TRH
| Goiter
503
Grave's disease and symptoms
Most common type of hyperthyroidism caused by autoimmune disease in which antibodies develop against TSH receptor
Characteristics include goiter in neck, bulging of eyes, increased BMR, increased sympathetic nervous system activation, palpilations
504
Hypothyroidism and symptoms
Caused by deficiency of I in diet
505
Primary thyroid dysfunction
Decrease in thyroid hormone leading to increased TSH and goiter
506
Hashimoto's thyroiditis
Autoimmune disease where antibodies are created against T3 and T4; goitre
507
Secondary hypothyrodism
Low levels of TSH are produced in pituitary gland
508
Tertiary hypothyroidism
Low levels of TRH
509
Cretinism
Hypothyroidism in utero
510
Myxedemia
Hypothyroidism in adults due to accumulation of edema and hyaluronic acid under skin
511
Steroid hormones are produced by?
Adrenal cortex
512
Precurser hormone for aldosterone?
Corticosterone
513
Only hormone to produce feedback inhibition is?
Cortisol
514
Steroidogenesis
Cholesterol is converted to biologically active steroid hormones
515
Adrenocorticotropin (ACTH)
Stimulates adrenal blood flow, adrenal growth, steroidogenesis
516
ACTH and Beta LPH are made from?
POMC (propriomelanocortin)
517
Increased POMC activity results in?
Increased MSH activity and increased skin pigmentation
518
Glomerular zone of adrenal cortex
Produces aldosterone, no metabolism
| outer zone
519
Fascicular zone
Produces cortisol, intermediate metabolism
| middle zone
520
Reticular zone
Produces androgens; sex characteristics
| inner zone
521
Conn's syndrome
Excess aldosterone leads to increased Na retention, therefore increased water retention leading to hypertension
522
How does cortisol increase blood glucose?
Through anabolic effects on liver (glucogenesis) and catabolic effects on peripheral tissues
523
Levels of cortisol throughout the day?
High first thing in the morning, decrease throughout the day and are lowest at the end of the day, rise during sleep
524
Addisons disease
Defect in adrenal cortex. Cortisol is not made and there is no feedback inhibition
Levels of ACTH are very high
Increased skin pigmentation due to high POMC activity
525
Secondary adrenal insufficiency
Defect at pituitary level...it does not make ACTH
| Does not have increased POMC levels
526
Primary adrenal insufficiency
Reduced cortisol secretion and reduced gluconeogenesis so hypoglycemia
527
Cushing's syndrome
Prolonged exposure to cortisol caused by tumour
528
Adrenal gland tumour
Produces high levels of cortisol adn cortisol inhibits ACHT production via feedback regulation
529
Ectopic tumour
Can produce ACTH which stimulates cortisol production
530
DHEA
Weak androgen synthesized in the zona reticularis
| Can be converted into estrogen or testosterone
531
Andrenogenital syndrome and symptoms
Biosynthetic pathways that make aldosterone and cortisol are deficient, and instead all the precursors that enter the pathway that makes DHEA
Masculiniation of female genitals
Hirsuitism
532
2 hypercalcemic hormones that regulate Ca and P
PTH and vitamin D
| Act to increase Ca levels in blood
533
Hypocalcemic hormone that regulates Ca and P
Calcitonin
| Acts to decrease Ca levels in blood
534
Parathyroid hormone acts to
Increase plasma Ca at the expense of plasma phosphate
535
PTH effect on kidney
Increased Ca reab, decreased P reab, increased vit D activation
536
PTH target sites
Kidney
Bones
GIT
537
Low levels of plasma Ca levels causes (what regarding PTH)
Stimulation of PTH secretion
538
High levels of plasma Ca levels causes (what regarding PTH)
Inhibition of PTH
539
Causes of hyperparathyroidism
Problem with parathyroid gland itself
| Low blood Ca
540
2 conditions that result in low blood Ca
Rickets (in children) and osteomalacia (adults)
541
Trousseau's sign
Hypoparathyroidism
| Involuntary contraction of carpal muscles due to hypercalcemia and tetany
542
Chvostek's sign
Hypocalcemia
Trigeminal nerve along neck
Tetany and snarl
543
Pseudohypoparathyroidism
Tissue insensitivity to PTH action (PTH receptors in tissue arent working)
544
As concentration of blood plasma increases what happens to calcitonin secretion?
Increases
545
Calcitonin in GIT
Calcitonin will directly inhibit Ca uptake
546
Where is calcitonin made?
Thyroid gland in parafollicular cells (C cells)
547
Photoisomerization occurs in response to?
UV light
548
How is vitamin D synthesized?
By the addition of hydroxyl groups in the liver and then in the kidney to inactive state
549
Effects of vitamin D
Increased plasma Ca and P concentration
550
Vitamin D deficiency in kids vs adults
Kids: rickets
Adults: osteomalacia
551
Vitamin D toxicity
Excess VD can result in tissue calcification which can lead to aneurysm
552
Where is the endocrine gland found?
Within the organ called Islet of Langerhans or pancreatic islets
553
Alpha cells secrete?
Glucagon
554
Beta cells secrete?
Insulin
555
Somatostatin
Made in the delta cells and acts as a hypothalamic releasing factor to inhibit secretion of TSH and GH
Also inhibits secretion of glucagon and insulin
556
What happens when beta cells release insulin?
Inhibits alpha cells
557
What happens when alpha cells release glucagon?
Stimulates alpha cells and delta cells
558
Which nerves are involved in pancreatic islet stimulation?
From parasympathetic: vagus nerve
| From sympathetic: splanchnic nerve
559
Sympathetic stimulation effect on glucagon and insulin?
Increased glucagon decreased insulin
560
Parasympathetic stimulation effect on glucagon and insulin?
Increased glucagon and insulin
561
Insulin actions. Anabolic or catabolic?
Lower blood glucose
Promotes conversion of nutrients to stored form
Anabolic
562
Glycogen actions. Anabolic or catabolic?
Increases blood glucose
Promotes breakdown of stored energy
Catabolic
563
What happens regarding insulin when you ingest food?
Parasympathetic release of insulin
564
What happens regarding insulin when you are stressed?
Sympathetic stimulation will inhibit insulin release
565
Primary stimulus for insulin release?
High plasma glucose levels
566
Primary stimulus for glucagon release?
Low plasma glucose levels
567
Diabetes mellitus
Insulin deficiency and glycogen excess
568
Type I diabetes mellitus
Autoimmune disease...body attacks beta cells
| Treated with insulin injections
569
Type II diabetes mellitus
Insulin resistance...body cant respond to insulin
Obesity occurs
Treated by regulating diet
570
Insulin excess
Due to insulin secreting tumour
| Reactive hypoglycemia
