Human Physiology Flashcards
(216 cards)
1
Q
What is an antidiuretic?
A
Stops you weeing
2
Q
What is vasopressin?
A
Antidiuretic hormone which makes the tubular wall more permeable to water for greater water reabsorption
3
Q
Where is vasopressin made and stored?
A
It is made in the hypothalamus and stored in the posterior pituitary gland
4
Q
What is a diuretic?
A
Makes you wee
5
Q
What is plasma clearance?
A
Volume of plasma completely cleared of a substance by the kidneys per minute (ml/min)
6
Q
What is the equation for plasma clearance?
A
Plasma clearance (ml/min) = urine conc per ml x urine flow (ml/min)/plasma conc per ml
7
Q
When does plasma clearance = gfr
A
When the substance is freely filtered and not reabsorbed e.g. Creatine and insulin
8
Q
What substance is used to estimate gfr?
A
Creatine since it is freely filtered and not reabsorbed
9
Q
What is not filtered out by the glomerulus?
A
Plasma proteins
10
Q
What 3 layers does a substance pass through to be filtered by the glomerulus?
A
Glomerular capillary wall
Basement membrane (acellular)
Inner layer of the bowman’s capsule
11
Q
What is the name of an arteriole leading to somewhere?
A
Afferent arteriole
12
Q
What is the name of an arteriole leading away from somewhere?
A
Efferent arteriole
13
Q
What forces are involved in glomerular filtration?
A
Glomerular capillary blood presure
Plasma colloid osmotic pressure
Bowman’s capsule hydrostatic pressure
14
Q
What is net filtration pressure?
A
Forces favouring filtration - forces opposing filtration
15
Q
What is GFR?
A
Glomerular filtration rate. Amount of fluid filtered through the glomerulus per min. Ml/min. Usually 125ml/min
16
Q
What is GFR usually?
A
125ml/min
17
Q
What does GFR depend on?
A
Net filtration
Glomerular surface area
Glomerular permeability
18
Q
What is the equation for GFR?
A
GFR = net filtration x glomerular surface area
19
Q
How are changes in blood pressure regulated in the glomerulus?
A
Increase BP = afferent arteriole vasoconstriction (less blood to glomerulus)
Decrease BP = afferent arteriole vasodilation (more blood to glomerulus)
20
Q
What is filtered load?
A
Amount of a substance filtered from the glomerulus per minute (mg/min)
21
Q
What is Tm?
A
Max amount of a substance that can be reabsorbed by the tubule per minute. Mg/min.
22
Q
What is the equation for filtered load?
A
Plasma conc x gfr
23
Q
What is Tm limited by?
A
The number of carriers present in the tubule membrane
24
Q
Equation for excretion of a substance?
A
Filtered load - Tm
25
What is an exocrine gland?
Secretes a substance onto epithelia via a duct
26
What is an endocrine gland?
Secretes hormone into the blood (no duct)
27
What are 7 functions of the kidney?
Excretion of metabolic waste products and foreign chemicals
Regulation of water and electrolyte levels
Regulation of acid/base levels
Regulation of arterial blood pressure
Regulation of rbc production
Secretion, metabolism and excretion of hormones (epo)
Gluconeogenesis
28
Which blood vessels supply nephrons?
Arcuate arteries
29
Which blood vessel supplies the glomerulus?
Afferent arteriole
30
What does the efferent arteriole in a nephron do?
Carries blood from the glomerulus to the peritubular capillaries
31
What are the 2 capillary beds in a nephron?
The glomerulus and the peritubular capillaries
32
Where are the peritubular capillaries found?
Around the loop of henle
33
How many nephrons in a kidney?
800,000 - 1,000,000
34
Can nephrons be regenerated?
No
35
What are the 5 barriers that must be crossed in reabsorption?
```
Luminal cell membrane
Cytosol
Basolateral cell membrane
Intersitial fluid
Capillary wall
```
36
What % of Na reabsorption takes place in the proximal tubule?
67%
37
What percentage of Na reabsorption takes place in the loop of henle?
25%
38
What percentage of Na reabsorption takes place in the distal and collecting tubules?
8%
39
Which substance promotes Na reabsorption?
Aldosterone
40
Which substances inhibit Na reabsorption?
Atrial natriuretic peptide
| Brain natriuretic peptide
41
What secretes aldosterone?
Adrenal cortex
42
What secretes renin?
Kidney
43
Which enzyme cleaves angiotensin 1 (10 aa) to angiotensin 2 (8aa)?
ACE
44
Where are natriuertic peptides stored?
Granules in the atria and ventricles
45
Do endocrine glands have ducts?
No
46
What are the 2 hormone groups?
Hydrophilic (peptides and catecholamines)
Lipophilic (steroid hormones and thyroid hormones)
47
What are the 7 major endocrine glands?
```
Hypothalamus
Pituitary gland
Thyroid
Parathyroid
Adrenal gland
Pancreas
Ovaries/testes
```
48
Which type of hormone can cross cell membranes?
Lipophilic hormones (steroids and thyroid hormones)
49
Which hormones have extracellular receptors?
Hydrophilic hormones (peptides and catecholamines)
50
What 5 things does aldosterone do?
Increases sodium potassium atpase channels on basolateral membrane
Increases sodium/chloride symporters on apical membrane
Increases Enac channels on apical membrane
Increases Enac activity by activating protein kinases
Increases Enac activity by activating prostatin which cleaves Enac precursors
51
How do steroid hormones travel in the blood?
Attached to carrier proteins
52
Which type of hormone is stored?
Peptide hormones
53
Which type of hormone is made on demand?
Steroid
54
Which type of hormone is broken down faster?
Peptide
55
What is the half life of peptide hormones?
Minutes
56
What is the half life of steroid hormones?
Hours
57
How long do the effects of peptide hormones last?
Minutes to hours
58
How long do the effects of steroid hormones last?
Hours to days
59
What connects the hypothalamus and the pituitary gland?
Infundibulum
60
What is permissiveness in terms of hormone control?
Where presence of one hormone is needed for another hormone to exert its full effect on target cells
61
Give an example of permissiveness
Thyroid hormone increases the effect of adrenaline on the liver and heart
62
What is synergism in terms of hormone control?
Several hormones combine to produce an effect greater than the sum of all their individual effects
63
Give an example of synergism?
Testosterone requires FSH for normal sperm production
64
What is antagonism in terms of hormones?
One hormone reduces the effect of another
65
Give an example of hormone antagonism
In pregnancy progesterone inhibits the effects of oestrogen on the uterus
66
Primary hypersecretion
Gland produces xs hormone
67
Give an example of primary hypersecretion
Cushings disease. Adrenal gland produces xs cortisol
68
Secondary hypersecretion
Too much tropic hormone
69
Primary hyposecretion
Gland secretes too little hormone due to non functioning gland or dietary deficiency
70
Give an example of primary hyposecretion due to a non functioning gland
Addisons disease - adrenal gland does not produce enough cortisol
71
Give an example of primary hyposecretion due to dietary deficiency
Shortage of thyroid hormone due to shortage of iodine in the diet
72
Secondary hyposecretion
Low secretion of a hormone due to low production of tropic hormone
73
Tertiary hyposecretion
Low secretion of hormone and tropic hormone due to low secretion of hypothalamus hormone
74
What connects the hypothalamus and the posterior pituitary gland?
Hypothalamo-hypophysial nerve tract
75
What are the 2 posterior pituitary gland hormones?
Oxytocin and vasopressin
76
Describe the structure of oxytocin and vasopressin?
9 amino acids
| Disulfide bond between 1 and 6 forming a ring
77
What type of receptors do oxytocin and vasopressin bind to?
G protein linked cell surface receptors
78
What transport protein is used to transport hormones from the hypothalamus to the posterior pituitary gland?
Neurophysin
79
Where are granules stored in the posterior pituitary gland?
Hering bodies
80
How are granules released from the posterior pituitary gland?
Calcium dependent exocyotosis
81
What second messenger system is associated with oxytocin?
IP3
82
What is the name for over production of vasopressin?
SIADH
83
What is the treatment for over production of vasopressin?
Vasopressin antagonist such as demeclocycline
84
What does vasopressin under production lead to?
Diabetes insipidus
85
What is the treatment for diabetes insipidus?
Synthetic vasopressin
86
What 3 effects does vasopressin have?
Increase cortisol
Increase water retention (aqp)
Increase blood pressure by vasoconstriction
87
What receptors are associated with vasopressin?
```
V1a = smooth muscle
V1b = corticotrophs
V2 = kidney
```
88
What second messenger system is associated with vasopressin?
V1 - IP3
| V2 - cAMP
89
Where is testosterone produced in women?
In the ovaries and adrenal glands
90
Where is testosterone produced in women?
In the ovaries and adrenal glands
91
How do men produce estrogen?
Aromatase converts testosterone to estradiol
92
What is acromegaly?
Excess growth hormone is produced after epiphyseal fusion
93
What is a feature of acromegaly?
Face coarsening. Bones cannot grow anymore due to epiphyseal fusion but tissues can still grow
94
What are 2 common cause of anterior pituitary hormone primary hypersecretion?
Pituitary adenoma and lack of suppression of hypothalamic trophic hormone
95
How does cushings disease lead to diabetes?
Increased cortisol means increased gluconeogenesis which can lead to insulin resistance and type 2 diabetes
96
Which thyroid hormone has a longer half life?
T4 (5 - 7 days as opposed to 1 - 3 days)
97
Which thyroid hormone is more abundent?
T4 (98%)
98
Where are thyroid hormone receptors found?
In the nucleus of target cells
99
How do men produce estrogen?
Aromatase converts testosterone to estradiol
100
What is acromegaly?
Excess growth hormone is produced after epiphyseal fusion
101
What is a feature of acromegaly?
Face coarsening. Bones cannot grow anymore due to epiphyseal fusion but tissues can still grow
102
What is a common cause of anterior pituitary hormone primary hypersecretion?
Pituitary adenoma
103
How does cushings disease lead to diabetes?
Increased cortisol means increased gluconeogenesis which can lead to insulin resistance and type 2 diabetes
104
On which part of the nephron does vasopressin act?
Distal tubule
105
What are the 3 types of sex hormones?
Oestrogens
Progesterones
Androgens
106
What are the 3 steps of spermatogenesis?
Mitosis
Meiosis
Cytodifferentiation
107
What are the 5 stages of the human life cycle?
```
Embryonic/foetal development
Infancy and childhood
Puberty and adolescence
Adulthood
Late adulthood/old age
```
108
What hormone changes are associated with menopause?
Increased FSH and LH levels. Decreased levels of progesterone and oestrogen due to decline in ovarian reserve
109
What are gonadotrophins?
FSH and LH
110
What are the symptoms of menopause?
Vasomotor
Psychological
Urogenital
Bone loss
111
What are the side effects of oestrogen hrt?
Breast tenderness
Bloating
Nausea
Headaches
112
What are the side the side effects of progesterone hrt?
Depression, mood swings
Skin changes
Abnormal bleeding
113
What are the risks of hrt?
Increased risk of breast and ovarian cancer
114
How does the COC pill work?
It blocks ovulation
Thickens cervical mucus
Creates a hostile endometrium which decreases the possibility of implantation should fertilisation occur
115
How does the progesterone only pill work?
Thickens cervical mucus
Creates a hostile endometrium so implantation cannot occur even if fertilisation takes place
116
Where is the site of fertilisation?
Ampulla of the oviduct
117
When does fertilisation usually occur?
24 hours after ovulation
118
How long can sperm survive?
48 hours usually but can survive up to 5 days in the female reproductive tract
119
Trace the journey of sperm through the female reproductive tract
Vagina, cervical canal, uterus, oviduct, ampulla
120
How does the female reproductive tract aid sperm migration?
Myometrium contractions
Upward contractions of the oviduct smooth muscle
Mature egg releases the chemoattractant allurin
121
Where does capacitation occur?
Female reproductive tract
122
What is capacitation?
Final maturation step that sperm undergo which allows them to penetrate and fertilise an egg
123
What occurs during capacitation?
Cholesterol is withdrawn from the membrane
Proteins are redistributed
Calcium enters the cell
124
Which two layers must a sperm penetrate to fertilise an egg?
Granulosa cells
Zona pellucida
125
How do sperm cells break through granulosa cells and the zona pellucida?
Acrosomal reaction
126
How long after fertilisation does a blastocyst move into the uterus?
3 days
127
How long after fertilisation does a blastocyst implant?
7 days
128
What are the 5 functions of the placenta?
Protection (from mother's immune system)
Nutrition
Excretion
Gas exchange
Hormone secretion (placenta is an endocrine gland)
129
When does the placenta start to form?
Day 7
130
When must the placenta be completely self sufficient by?
Week 12
131
How long does the corpus luteum survive in pregnancy?
Around 10 weeks
132
Describe the signalling pathway used in liver regeneration?
Hippo pathway. Yap stays in the cytoplasm if a cell has neighbours, yap moves to the nucleus if a cell does not have neighbours
133
What is the name of macrophages in the liver?
Kupffer cells
134
What is the main haematopoietic organ up until 5 months of gestation?
Liver
135
Mammogenesis
Development of mammary glands
136
When does Mammogenesis occur?
Pregnancy
137
Lactogenesis
Development of lactation
138
Galactopoiesis?
Maintenance of lactation
139
Explain the contraceptive effect of breastfeeding
Prolactin inhibits GnRH secretion by the hypothalamus, resulting in amenorrhoea
140
How does dopamine affect breast feeding?
It inhibits prolactin so stops lactation
141
What are the advantages of breast feeding?
Less chance of breast cancer (especially triple negative, hard to treat breast cancer), immune transfer to baby, uterus returns to normal size quicker (oxytocin released by suckling)
142
What stimulates milk production?
Drop in oestrogen, progesterone, prolactin and hCS at birth. Suckling is required to stop prolactin levels dropping further and lactation stopping. At weaning when suckling stops prolactin levels drop and lactation stops.
143
What is breast milk made up of?
90% water
| 7% lactose
144
How many calories in 100ml of breast milk?
70 kcal
145
What pH is breast milk?
7
146
What are the 3 stages of breast milk?
Colostrum
Transitional milk
Mature milk
147
What is involution?
When the breasts stop producing milk after weaning
148
What are the differences between colostrum and mature milk?
Colostrum has less lactose and fat but has more IgG, protein, minerals and fat soluble vitamins
149
What is priapism?
Persistant painful erection
150
What are the main causes of erectile dysfunction?
Vascular disease (diabetes mellitus)
Neurogenic
Hormonal
Pharmacological
Psychological
151
How does viagra work?
It is a PDE-5 inhibitor which inhibits breakdown of cGMP. More cGMP = more smooth muscle relaxation in trabeculae = erection
152
What are the 3 layers of the adrenal cortex and what do they each produce? (From outermost to innermost layer)
The zona glomerulosa produces aldosterone
The zona fasciculata produces cortisol
The zona reticularis produces sex steroids
153
What cells are found in the adrenal medulla?
Adrenal chromaffin cells
154
What do adrenal chromaffin cells secrete?
Catecholamines
155
What are catecholamines?
Adrenaline
Noradrenaline
Dopamine
ATP
156
What is pheochromocytoma?
Tumour of adrenal chromaffin cells which secretes high amounts of catecholamines
157
What is an advantage of the POP over the COCP?
POP has no oestrogen (oestrogen promotes thrombosis) so POP does not increase risk of DVT.
158
Who is not permitted to use the COCP and why?
Women with sickle cell disease. Sickle haemoglobin polymerises when deoxygenated.
159
How do the POP and the COCP stop ovulation?
Inhibit FSH and LH secretion by the hypothalamus
160
What are the symptoms of PCOS?
Obesity
Androgenic features
Amenorrhagia (no ovulation)
161
What is the mechanism of PCOS?
High LH and insulin levels work synergistically to increase ovarian growth and androgen production
162
Which type of immunoglobulin is found mainly in breast milk and why?
IgA for protection against enteric infection
163
Why does cushings syndrome cause increased androgen levels?
Because cushings syndrome is a defect of the adrenal cortex where androgens are made
164
Which two cell types are found in the distal and collecting tubules?
Intercalated cells (acid base balance)
Principal cells (aldosterone and vasopressin)
165
What things do natriuretic peptides do to inhibit Na+ reabsorption?
Inhibit aldosterone secretion from adrenal cortex
Inhibit secretion and action of vasopressin
Inhibit renin secretion by kidney
Increase GFR by increasing BP in glomerulus by afferent arteriole vasodilation and efferent arteriole vasoconstriction
166
What is the result of natriuretic peptide secretion?
Increased Na+ and accompanying osmotic water excretion from the urine
167
Which natriuretic peptide is more effective?
ANP
168
What is the name of the sodium glucose cotransporter?
SGLT
169
What is a symporter?
Uses the movement of one substance with its conc gradient to transport another substance against its conc gradient across a membrane. Both substances are moving in the same direction.
170
What is an antiporter?
Uses the movement of one substance with its conc gradient to transport another substance against its conc gradient across a membrane. The substances are moving in opposite directions
171
What is the name of the glucose transporter on the basolateral membrane of tubule cells which transports glucose with its conc gradient?
GLUT
172
What are the 2 types of aquaporins and how are they different?
Aqp 1 is found in the proximal tubule and is always open
Aqp 2 is found in the distal tubule and is under the control of vasopressin
173
What is the role of probenecid?
It allows penicillin to stay in the body longer
174
What are acid sources?
Lactic acid
Ketoacids (diabetes mellitus)
CO2
175
How is pH homeostasis maintained?
Ventilation
Buffers
Kidneys
176
Where are aquaporins 2 stored in principal cells?
Vesicles
177
What is nocturnal enuresis?
Bed wetting due to reduced vasopressin secretion at night
178
What is pharmacodynamics?
What the drug does to the body
179
What is pharmacokinetics?
What the body does to the drug
180
What is the difference between agonists and antagonists?
Agonists activate receptors
| Antagonists block receptors
181
Biased agonism
Different ligands bind to the same receptor and cause activation of different pathways
182
Ec50
Dose which gives response at 50% of maximum
183
What is osmotic diuresis?
Increase in urination rate
184
What is bioavailability?
The proportion of a drug that enters circulation
185
What type of diuretic would you use to treat hypertension and why?
Thiozide. It blocks Na/Cl channels on the apical membrane of epithelial cells in the distal tubule
186
Which type of diuretic would you use to treat liver disease and why?
Potassium sparing diuretic because they block Na/K exchange in the collecting tubule
187
Which type of diuretic would you use to treat water retention?
Loop diuretic
188
Which type of diuretic would you use to treat kidney disease?
Potassium sparing or loop
189
Which type of diuretic would you use to treat heart failure?
Potassium sparing or loop
190
Name the 5 types of diuertic and say where they act
```
Osmotic (PCT)
Loop (ascending loop of henle)
Carbonic anhydrase inhibiting
Thiazide (DCT)
Potassium sparing (collecting tubule)
```
191
Which type of diuretic would you use to treat cerebral oedema or glaucoma?
Osmotic (mannitol)
192
Name a loop diuretic
Furosemide
193
Name a thiozide
Bendroflumethiozide
194
Name a potassium sparing diuretic?
Amiloride
195
Which diuretics are sulfonamides?
Loop diuretics
| Thiozides
196
Which diuretic is the only one which reduces renal blood flow?
Thiozide
197
Which diuretic has the longest half life?
Amiloride (6 - 9 hours)
198
Which diuretics are associated with gout?
Mainly thiazide but also loop
199
How is mannitol administered?
IV
200
Which diuretic has the shortest half life?
Furosemide (less than 100 mins)
201
What is the half life of a drug?
The amount of time for the concentration of a drug in the body to be reduced to half the original value
202
What is desmopressin?
Synthetic vasopressin
203
How is furosemide administered?
Oral
IV
IM
204
How is bendroflumethiozide administered?
Oral
205
How is amiloride administered?
Oral
206
What are the 4 processes associated with pharmacokinetics
```
Adme
Absorption
Distribution
Metabolism
Excretion
```
207
What is MTC in terms of pharmacokinetics?
Maximum tolerated concentration
208
What is MEC in terms of pharmacokinetics?
Minimum effective concentration
209
What does intrathecal mean?
Into the spinal cord
210
What are the 4 main body fluid compartments?
Plasma
Interstitial fluid
Transcellular fluid
Intracellular fluid
211
Which type of molecules can pass through the blood brain barrier?
Lipophilic
212
Why would you administer a drug intrathecally?
Because it can bypass the blood brain barrier
213
Volume of distribution
Volume into which the drug appears to be distributed with a concentration equal to that in the plasma
214
Why is relatively little lipophilic drug found in the plasma?
A lot gets sequestered in adipose tissue
215
What is the main site of drug metabolism and the site of first pass metabolism?
Liver
216
Damage to which part of the spinal cord causes back pain?
Sciatic nerve
