SUGER Flashcards
(109 cards)
1
Q
What 3 things does growth hormone stimulate
A
Protein synthesis
Lipolysis
Glucose metabolism
2
Q
Name the 3 controlling steps of RAAS initiation
A
macula densa in the distal convoluted tubule detect LESS NaCl in the tubule
• Sympathetic stimulation
• Little or no arteriolar stretch (i.e. low blood volume due to the lack of Na+ and thus H2O)
3
Q
What releases renin
A
Renin is secreted by juxtaglomerular cells located in the afferent arterioles
4
Q
What cleaves angiotensinogen to angiotensin I
A
Renin
5
Q
Where is angiotensinogen produced
A
Liver
6
Q
Describe the conversion of angiotensin I to angiotensin II
A
Angiotensin I is biologically inactive
Cleaved to angiotensin II (active agent) by angiotensin-converting enzyme (ACE)
7
Q
Where is ACE produced
A
Lungs
8
Q
How does angiotensin II cause the secretion of aldosterone
A
Stimulates the cells of the zona glomerulosa in the adrenal cortex of the supradrenal/adrenal glands to secrete the steroid hormone called ALDOSTERONE
9
Q
What is the effect of angiotensin II on bp
A
Is a vasoconstrictor, which results in vasoconstriction especially at the efferent arteriole, this in turn results in the increase in pressure resulting in an increased GFR
10
Q
How does aldosterone cause increase blood volume
A
Aldosterone acts on principal cells of the collecting duct which results in increased Na+ and H2O reabsorption
11
Q
What effect does angiotensin II have on the hypothalamus
A
Stimulates thirst and ADH release resulting in water retention
12
Q
Why is creatinine used as a marker substance
A
Freely filtered
Not metabolised
Not secreted or reabsorbed
13
Q
Where is atrial natriuretic peptide synthesised and secreted from
A
Cardiac atrial cells
14
Q
Effects of ANP
A
Acts as a renal vasodilator > afferent arteriole dilator > increased GFR
Inhibits Na+ reabsorption
Inhibits aldosterone
15
Q
What is parathyroid hormone released in response to
A
Low plasma [Ca2+]
16
Q
Effect of PTH on the distal tubule when [Ca] is low
A
PTH binds with receptors and causes an increase in Ca2+ uptake from the tubule
Stimulates the formation of Vit D
17
Q
What are the 2 cell types found in the CT
Give their functions
A
Principal cells - respond to aldosterone and ADH, reabsorption of Na and water
Intercalated cells - secrete acid or HCO3
18
Q
Functions of skin
A
- Barrier to infection
- Thermoregulation
- Protection against trauma
- Protection against UV
- Vitamin D synthesis
- Regulation of H2O loss
19
Q
What are the 3 basic layers of the skin
A
Epidermis
Dermis
Subcutaneous tissue
20
Q
What are the layers of the epidermis
A
Stratum corneum S lucidum S granulosum S spinosum S basale
Come Let’s Get Sun Burnt
21
Q
How does the skin prevent transepidermal water loss
A
Tight junctions between cells in stratum granulosum, epidermal lipids and keratin in stratum corneum
22
Q
Which layer of the skin is vitamin D stored
A
Subcutaneous layer
23
Q
What is the pH of healthy skin
A
5.5
24
Q
Describe the healthy skin barrier
A
1) filaggrin produces natural moisturising factor (NMF) - this helps maintain skins hydration and an acidic environment on the outer surface of the stratum corneum
2) Balance the introduction of new cells in the basal layer.
3) lipid lamellas keep water inside the cell. Irritant and allergens tend to bounce off surface of skin
25
What is the affect of an increased pH on the skin
Degradatory proteases are no longer inhibited so they breakdown the corneodesmosomes
Increase pH also impairs the formation of lipid lamellae - allows skin cells to move apart which reduces water retention
26
What are sebaceous glands responsible for
Producing a lipid rich sebum which protects the hair
27
When does acne occur
When hair follicles become blocked with sebum, bacteria and skin cells
28
What type epithelium is found in skin
Keratinising stratified squamous epithelium
29
What is the arterial supply to the adrenals
* Superior adrenal artery from inferior phrenic
* Middle adrenal artery from abdominal aorta
* Inferior adrenal artery from renal artery
30
What is the difference in venous drainage between the right and left adrenals
Right adrenal vein drains directly into IVF
| left adrenal vein drain first into the left renal vein then into the IVF
31
What innervates the adrenals
Splanchnic nerve
32
What are the 3 parts of the adrenal cortex (outer to inner)
| State what each produce
Zona glomerulosa - produces mineralocorticoids (aldosterone)
Zona fasciculata - glucocorticoids (cortisol)
Zona reticularis -Sex steroids (androgens) and cortisol
GFR, Make Good Sex
33
Which hormones are secreted from the adrenal medulla
Adrenaline
| Noradrenaline
34
What is the precursor to all corticosteroids
Cholesterol
35
What % of cortisol in circulation is free
5%
36
Functions of cortisol
```
Inhibit growth and reproduction
Reduction of inflammation
Reduction of bone formation
Gluconeogenesis and carb metabolism
Proteolysis and lipolysis
```
37
What is the effect of adrenaline and noradrenaline when released in response to stress
```
Increase HR and BP
dilates pupil
Inhibits insulin release
Increases glucagon release
Increase in sweating
```
38
What are the receptors for adrenaline and noradrenaline
Adrenaline - high affinity beta receptors
| Nor - high affinity alpha
39
What affect does cortisol have on insulin
Antagonistic affect as it stops it from acting in cells as cortisol wants to maintain high blood glucose for stressful situations
40
What spinal levels does the thyroid gland sit between
Anterior neck between C5 - T1
41
What divides the thyroid into its left and right lobe
The isthmus
42
What 2 muscles does the thyroid lie between
Sternohyoid and sternothyroid muscle
43
What can be found on the posterior surface of the thyroid
4 parathyroid glands
44
What is the blood supply to the thyroid
Superior thyroid arteries
- 1st branch of external carotid artery
- Supplies anterior and superior portions
Inferior thyroid arteries
- branch of subclavian artery
- Supplies posterior and inferior aspect
45
What innervates the thyroid and parathyroid gland
Sympathetic trunk
46
Name the thyroid hormones T3 and T4
T3 - triiodothyronine
| T4 - thyroxine
47
Describe the process of thyroid hormone secretion ( hypothalamic-pituitary-thyroid axis)
- Thyrotropin releasing hormone (TRH ) released by hypothalamus in response to neural inputs
- TSH then released by anterior pituitary gland
- This acts on thyroid gland to secrete T3 and 4
- T4 is converted to T3 and acts on its target cells
- TSH and TRH are inhibited through negative feedback
48
What are the metabolic actions of T3
- stimulates carb absorption in small intestine and increases fatty acid release from adipocytes
- maintain high BMR
- increases body temp
49
How is T3 important in brain maturation
- formation of axon terminals
- formation of synapses
- growth of dendrites and dendritic extensions
- formation of myelin
50
What is the physiological difference between T3 and 4
T4 is most abundant but T3 is the biologically active form of T4
51
Where do the parathyroid glands drain into
Thyroid plexus
52
Function of parathyroid glands
Regulate calcium and phosphate levels
| Secretes parathyroid hormone in response to low Ca or high phosphate
53
Effects of PTH
• Increases calcium reabsorption in renal distal tubule
• Increases intestinal calcium absorption (via activation
of vitamin D) – duodenum and jejunum
• Increases calcium release from bone (stimulated
osteoclasts activity)
• Decreases phosphate reabsorption
• Binds to G protein coupled receptors
54
Describe the difference in shape between right and left adrenal glands
Right is pyramidal
| Left is crescent shaped
55
The kidneys are encased in layers of fat and fascia
| Give them deep to superficial
Renal capsule – tough fibrous capsule.
Perinephric fat – collection of extraperitoneal fat.
Renal fascia (also known as Gerota’s fascia or perirenal fascia) – encloses the kidneys and the suprarenal glands.
Paranephric fat – mainly located on the posterolateral aspect of the kidney.
56
What is the difference between positive and negative feedback
Negative - as a hormone increase in [ ], it INHIBITS the release of another
In positive feedback it PROMOTES the release of another
57
Name the 6 hormones produced by the anterior pituitary
| hint: FLAGTOP
```
FSH – Follicle Stimulating Hormone
LH – Luteinizing Hormone
ACTH – Adrenocorticotropic hormone
GH – Growth Hormone
TSH – Thyroid Stimulating Hormone
O - ignore
Prolactin
```
58
Name the 2 hormones produced by the posterior pituitary gland
ADH/ Vasopressin
| oxytocin
59
What are hypophysiotropic hormones
Hypothalamic hormones that control secretion of anterior pituitary
hormones
60
What is the name of the hypophysiotropic hormone that stimulates the release of LH and FSH
Gonadotropin-releasing hormone (GnRH)
61
What effect does (LH) and (FSH) have on males
LH - stimulates production of testosterone by leydig cells
| FSH - Stimulates spermatogenesis by stimulating sertoli cells to produce androgen binding protein
62
What effect does luteinising hormone (LH) and follicle stimulating hormone (FSH) have on females
LH -> Stimulates ovulation + ovarian follicle maturation + corpus luteum formation.
FSH -> regulates development + growth of ovarian follicle + affects 1st half of menstrual cycle
63
Name the hypophysiotropic hormone that stimulates the release of ACTH
Corticotropin-releasing-hormone
64
Describe the HPA axis
| Adrenal
Corticotropin releasing hormone stimulates Adrenocorticotropic hormone which causes an increase in cortisol production in the zona fasciculata of adrenal cortex
65
Name the hypophysiotropic hormone that stimulates the release of growth hormone
Growth hormone releasing hormone (GHRH)
66
What processes are GH involved in
```
Skeletal growth and bone density
Muscle strength
Protein synthesis
Glycogenolysis
Lipolysis
```
67
What hormone inhibits GH
somatostatin
68
Where is GH produced
Somatotrophs
69
What causes the release of prolactin
Suckling
| Thyroid releasing hormone
70
What inhibits the release of prolactin
dopamine
71
Functions of prolactin
Initiate breast milk production
| Maintain milk production once established
72
How are the anterior and posterior pituitary different
- Anterior has no neural connection to hypothalamus while posterior does
- posterior pituitary STORES and releases hormones, anterior SYNTHESISES and releases hormones
73
Where is oxytocin synthesised
paraventricular nucleus of hypothalamus
74
Function of oxytocin
- Contraction of smooth muscle in the breast to promote milk ejection during lactation
- acts on the uterus to cause uterine contractions during labour-> promoting onset of labour
- Exerts positive feedback on itself
75
Where is anti diuretic hormone produced
Supraoptic nucleus of hypothalamus
76
Give 5 things that ADH is released in response to
* Increased osmotic pressure in blood
* Decreased blood volume
* Trauma/stress
* Increased PCO2
* Decreased PO2
77
Describe the negative feedback of ADH
- Osmoreceptors in the hypothalamus detect change
- ADH binds to V2 receptors on the collecting ducts -> increased expression of aquaporin 2 in cortical collecting duct
- This allows the passage of water from the CD into the blood to reduce the plasma osmolality -> ↑water reabsorption and blood volume
- vasoconstriction of SM cells around blood vessels increases bp
78
How does the anterior pituitary receive its blood supply
through portal venous circulation called hypothalamo-hypophyseal portal vessels
79
What are the 3 main cell types in islets of langerhans
| State what each release
* Delta cells - somatostatin (inhibitors)
* Alpha cells - glucagon
* Beta cells - insulin
80
How is the active form of insulin produced
A and B chains connected by C peptide - proinsulin
| Insulin is produced when C peptide is cleaved
81
Function of insulin
* Reduces glucose output by liver
* Increase storage of glucose, FA + aa
* Stops breakdown of fat + muscle
82
Describe the feedback loop when blood glucose rises
Insulin is released and glucagon release is inhibited
There is increased glycogenesis in the liver and muscles
Gluconeogenesis is inhibited
83
Describe the feedback loop when glucose levels fall
Glucagon is released and insulin release is inhibited
Glycogenolysis occurs to release glucose from the liver and muscles into the blood
Gluconeogenesis occurs
84
Glucose moves into beta cells via which channel
GLUT2 channel
85
What causes depolarisation of the beta cells membrane
Metabolism of glucose occurs which makes ATP
ATP causes the closure of ATP-sensitive potassium channels
This causes the membrane to depolarise
86
How is insulin released from beta cells after membrane depolarisation
Depolarisation causes voltage-gated Ca channels to open inducing an influx of Ca2+
Ca2+ binds to vesicles containing insulin
These vesicles fuse with the cell membrane and release insulin
87
How does insulin cause a decrease in blood glucose level after leaving beta cells
Insulin binds to insulin receptors on muscle + fat cells
Triggers intracellular signalling cascade -> mobilisation of intracellular GLUT4 vesicles to cell membrane
GLUT4 vesicle integrates into cell membrane -> ↑number of membrane glucose transporters -> ↑rate of glucose facilitated diffusion (uptake) into cell -> ↓blood glucose level
88
What secretes melatonin
pineal gland
89
What do C cells secrete
calcitonin
90
What 3 cells does the parathyroid contain
chief cells
oxyphils
adipocytes
91
Histologically, what can be used to determine whether the specimen is thyroid or parathyroid
Thyroid may contain calcium oxalate crystals but parathyroid wont
92
Where are islets of langerhans most abundant in the pancreas
pancreatic tail
93
What is the most prominent layer of the adrenal cortex
Zona fasciculata
94
Where is spermicide produced
Seminiferous tubule
95
Anatomy of the testes : SREEVE UP
```
Seminiferous tubules
Rete testes
Efferent ducts
Epididymis
Vas deferens
Ejaculatory duct
Urethra
Penile urethra
```
96
What is syngamy
Fusion of the male and female pronuclei
97
What does a pregnant womens ‘water breaking’ describe
Amniotic sac ruptures, amniotic fluid flows through the vagina
98
Parasympathetic innervation to detrusor
Pelvic splanchnic nerve
| S2-4
99
Sympathetic innervation of detrusor
Hypogastric nerve
| T12-L2
100
Describe branching of the renal artery
Renal artery -> segmental arteries -> interlobar arteries -> arcuate arteries -> interlobular arteries -> afferent arterioles -> glomerular capillaries -> efferent arteriole -> peritubular capillaries
101
What innervates the external urethral sphincter
Pudendal nerve
| S2-4
102
Where are C cells located
Thyroid gland
103
Which layer of the epidermis is acellular
Stratum corneum
104
Primary event in the switch from storage to voiding
Relaxation of urethral sphincter
105
What effect does aldosterone have on transporter protein in DCT
Increase in Na - K exchange transporters
106
What are incretins
Secreted by endothelial cells in GI tract.
| Functions to increase the effect of insulin in response to glucose
107
Give 2 examples of incretins
Glucagon like peptide
| Glucagon dependent insulinotropic peptide
108
Epithelium lining the vas deferens
Pseudostratified columnar
109
What secretes relaxin
Placenta and ovaries
