SUGER Flashcards
1
Q
What does Onuf’s nucleus do?
A
Controls the rhabdosphincter muscle which is voluntary
2
Q
What is the rhadosphincter?
A
A striated muscle sphincter - it is part of the external urethral sphincter
3
Q
What are the types of incontinence?
A
Stress incontinence
Urge incontinence
Retention with overflow
4
Q
What is the lower urinary tract comprised of?
A
Bladder
Bladder neck
Prostate gland (in man)
Urethra and urethral sphincter
5
Q
What is the function of the lower urinary tract?
A
To convert the continuous process of excretion into an intermittent and controlled process
6
Q
What does micturition mean?
A
The discharge of urine from the bladder
7
Q
What is stress incontinence?
A
A condition found mainly in women in which there is involuntary discharge of urine when the pressure of the abdomen increases suddenly e.g. jumping or coughing
8
Q
What is urge incontinence?
A
A condition where you have an urgent desire to go to pass urine and there is often leakage - this is due usually to an overactive bladder
9
Q
What is retention with overflow?
A
This is where there is an obstruction and this leads to difficulty fully passing urine - pressure build ups lead to frequent leaks
10
Q
What are the three main functions of the kidneys?
A
1) Excretion of waste products
2) Maintenance of salt, water and pH balance
3) Endocrine function - secreting hormones
11
Q
What parts of the nephron are in the cortex of the kidney?
A
- Bowman’s capsule
- Proximal tubule (convoluted part)
- Distal tubule
12
Q
What parts of the nephron are in the medulla of the kidney?
A
- Loop of Henle
- Collecting duct
13
Q
What is the structure of the loop of Henle?
A
- Thin descending limb
- Thin ascending limb
- Thick ascending limb
14
Q
What proportion of the cardiac output is received by the kidneys (both together)?
A
1/5th - 1L/min
15
Q
What is the normal urine flow per minute?
A
1ml/min
16
Q
What are the divisions of the renal arteries in the kidneys?
A
Renal artery Interlobar artery Arcuate artery Interlobular artery Afferent arteriole Glomerular capillary Efferent arteriole
17
Q
What is the glomerulus?
A
A capillary tuft that is fenestrated and lined on the outside by podocytes with foot process
18
Q
What is the role of the podocytes and their foot processes?
A
To aid in the filtration - regulating the passage of proteins from the capillary into bownmans space
19
Q
What is the role of mesangial cells in the glomerulus?
A
They alter the filtration rate by contracting and reducing the surface area of the glomerulus
20
Q
What is the approx. surface area of the glomerulus?
A
1m squared
21
Q
What makes up the filtration barrier?
A
1) Capillary endothelium
2) Basement membrane
3) Foot process and podosytes
22
Q
What determines the what crosses the filtration barrier?
A
1) Pressure
2) Size of molecule
3) Charge of the molecule
4) Rate of blood flow
5) Binding to plasma proteins e.g. calcium and hormones such as thyroxine
23
Q
Negatively charged anions are repelled at the barrier, why?
A
The basement membrane has a fixed negative charge
24
Q
What factors favour filtration into bowman’s space?
A
Increased hydrostatic pressure of capillary
Decreased oncotic pressure of capillary
25
What factors favour moevement of filtrat back into the capillary?
Decreased hydrostatic pressure of capillary
| Increased oncotic pressure of capillary
26
What is the glomerular filtration rate?
The filtration volume per unit of time
27
What is the equation for GFR?
GFR = Kf (Pgc-Pbs) - (Onc.gc)
28
What affect on GFR would the constriction of the afferent arteriole have?
It would decrease
29
What affect on GFR would constriction of the efferent arterioles have?
It would increase
30
What affect would dilation of the afferent arteriole have on GFR?
It would increase
31
What affect would dilation of the efferent arteriole have on GFR?
It would decrease
32
What is the name of the process in which renal blood flow is maintained?
Autoregulation
33
What is Tubuloglomerular feedback? Describe it
This is where GFR is regulated by the by the following:
1) Macula densa cells detect NaCl arrival
2) Macular densa release prostaglandins in response to reduced delivery
3) Prostaglandins trigger renin release from granular cells
4) Renin activates renin-angiotensin system
5) GFR increases
34
What three characteristics must a substance have to be used to measure GFR?
1) Freely filtered
2) Not secreted or absorbed in tubules
3) Not metabolised
35
How can GFR be calculated using a marker substance?
GFR = Conc in urine x flow rate/Conc in plasma
36
What is the normal GFR?
approx. 125ml/min
37
What substance is used clinically to meausre GFR?
Creatinine
38
What is the filtration fraction equation?
FF = GFR/Renal plasma flow
39
What is the normal filtration fraction?
20%
40
What is the concept of renal clearance?
The colume of plasma from which a substance is completely removed by the kidney per unit of time (usually a minute)
41
What is the calculation for renal clearance?
Clearance = Urine concentration x urine volume/plasma concentration
42
What does it mean if the renal clearance of a substance in lower than the GFR?
That it is freely filtered but partially reabsorbed?
43
What does it mean if the renal clearance of a substance is the same as the GFR?
That it is freely filtered and not absorbed or secreted
44
What does it mean if the renal clearance of a substance is greater than the GFR?
that it is freely filtered and secreted
45
What is the volume of filtrate produced each day?
180L
46
What happens at the proximal tubule?
```
Bulk reabsorption of:
Na+
Cl-
Glucose
Amino acids
HCO3-
```
Secretion of organic ions
47
What happens in the Loop of Henle?
1) More Na+ reabsorption
2) Urinary dilution
3) Generation of hypertonic medullary interstitium
48
What happens at the distal tubule?
1) Fine regulation of: Na+, K+, Ca2+, Pi
| 2) Seperation of Na+ and H2O
49
What happens at the collecting duct?
1) Similar to distal tubule
2) Acid secretion
3) Regulated H2O reabsorption
50
Does the proximal tubule have high or low permeability to water?
High
51
What is the bulk reabsortion driven by?
1) Basolateral Na/K ATPase
| 2) Secondary active transport for glucose, amino acids and lactate
52
What is secondary active transport?
Where the energy used to move a substance across a membrane is not directly from ATP e.g. by an electrochemical gradient
53
What is glomerulotubular balance?
Where a greater filtered load is matched by more proximal tubular reabsorption
1) Greater filtration load increases oncotic pressure in peritubular capillaries
2) Efferent arteriolar constriction reduces peritubular capillary hydrostatic pressure
54
Which part of the Loop of Henle is permeable to water?
Descending limb - ascending limb is impermeable
55
What occurs in the thick ascending limb?
Solute reabsorption
56
What is the name for the process in which a hypertonic medullary interstitium is generated?
Countercurrent multiplication
57
Describe the process of countercurrent multiplication
1) Solute reabsorption occurs in the ascending limb i this increases the medullary osmolarity
2) This draws water out from the descending limb which increases luminal osmolality
3) This causes the process to repeat increasing interstitium osmolarity
58
What are the two types of cell present in the collecting ducts?
1) Principal
| 2) Intercalated
59
What cells in the collecting duct are affected by ADH?
Principal cells
60
What is the role of principal cells?
Involved in sodium/potassium balance via sodium and potassium channels
61
What is the role of intercalated cells?
Involved in acid-base homeostasis
62
What are the limits of urine volume?
400ml-20L/day
63
What actions does angiotensin II have?
1) Vasoconstrictor
2) Stimulates aldosterone release
3) Increases Na reabsorption of proximal tubule
64
What is the action of ANP?
1) Renal vasodilator
2) Inhibits aldosterone release
3) Closes ENaC channels in collecting tubules
65
What is the normal pH range for blood?
7.35 to 7.45
66
Briefly describe how bicarbonate reabsorption occurs
1) Hydrogen ions are pumped into lumen of tubule
2) Bicarbonate and hydrogen ion form carbonic acid
3) Carbonc acid is broken down by carbonic anhydrase to CO2 and H2O
4) CO2 and H2O diffuse into cell
5) Recombine to form carbonic acid with CA enzyme
6) Dissociation occurs - HCO3- is pumped into capillary, H+ pumped back out into lumen
67
How does phosphate act as a buffer?
1) Alkaline phosphate accepts proton
2) Acid phosphate is impermeable to apical membrane
3) H+ don't pass into capillaries - excreted
68
How does the urinary ammonia buffer work?
1) NH3 sythesised from glutamate
2) NH3 diffuses into lumen
3) NH4+ is impermeable to apical membrane
4) Excreted
69
What type of compensation takes place in respiratory acidosis?
Renal compensation
70
What is the renal compensation for respiratory acidosis?
1) H+ secretion increases
2) Acid excreted as ammonium
3) HCO3- increases further
71
What is the renal compensation for respiratory alkalosis?
1) H+ secretion decreases
2) H+ retained
Note: Insufficient H+ secretion for HCO3- reabsorption
72
What happens to HCO3- and CO2 in Respiratory acidosis?
HCO3- increases
| CO2 increases
73
What happens to HCO3- and CO2 in respiratory alkalosis?
HCO3- decreases
| CO2 decreases
74
What happens to HCO3- and CO2 in metabolic acidosis?
HCO3- decreases
| CO2 decreases
75
What happens to HCO3- and CO2 in metabolic alkalosis?
HCO3- increases
| CO2 increases
76
What two hormones do the kidneys release?
1) Erythropoietin
| 2) Renin
77
What is the function of erythropoietin (EPO)?
Stimulates bone marow - promotes RBC maturation
78
Where is EPO made?
Peritubular cells in interstitial space of renal cortex
79
What does the urinary system originate from embryologically?
Intermediate mesoderm
80
What are the three overalpping kidney systems that develop from the intermediate mesoderm?
1) Pronephros
2) Mesonephros
3) Metanephros
81
Which of the three overlapping embryological systems does the permenant kidney form from?
Metanephros
82
What does the pronephros comprise of?
7-10 solid cell groups called Nephrotomes (they disappear at the end of the fourth week)
83
What does the mesonephros comprise of?
A ridge and a duct - the duct is lateral to the ridge (appears at 4th week)
84
Where does the urogenital ridge form?
On the medial side of the mesonephric ridge
85
What are the two sources of the metanephros system?
1) Metanephric blastema
| 2) Ureteric bud
86
What does the metanepheric blastema give rise to?
Excretory units
87
What does the ureteric bud give rise to?
Collecting system
88
Describe what happens as the ureteric bud forms the collecting system?
1) Dilates - forms renal pelvis
2) Splits - future major calyces
3) Major calyces bud to form minor cayces and collecting tubules
89
What is the position of the kidneys in development?
Develop in pelvis then move cranially
90
How does the blood supply change to the kidneys during development?
In pelvis they receive pelvic branches of aorta but when they ascend they receive blood directly from aorta - lower vessels usually degerate
91
At what point does the metanephros start functioning?
12th week
92
Where does the urogenital sinus come from?
Cloaca - divided by urorectal septum
93
What are the parts of the urogenital sinus? What do they form?
Upper - Urinary bladder
Pelvic (middle) - Prostatic and membranous urthra
Phalic - Penile urethra
94
How does the prostate develop (briefly)?
Prostatic urethra proliferates forming outgrowths (endodermal origin)
Prostate connective tissue and smooth muscle is mesoderm in origin
95
Which parts of the hindgut remain intraperitoneal?
Transverse colon - maintains dorsal mesentery
| Sigmoid colon - also retains mesentery
96
Which part of the hingut is retroperitoneal?
Descending colon - loses mesentery
97
What type of organs are the rectum and anal canal?
Infraperitoneal - develop in intraperitoneal space
98
What does the cloaca divide into?
1) Primitive urogenital sinus
| 2) Anorectal canal
99
What is the epithelial lining of the anal canal?
Upper 2/3 = Simple columnar
| Lower 1/3 = stratified squamous
100
What is the name of the line which divides the upper 2/3 and lower 1/3 of the anal canal?
Pectinate line
101
The lower 1/3 of the anal canal differs superiorly and inferiorly, how?
Superiorly - stratified non-keratinized squamous epithelium
Inferiorly - stratified keratinized squamous epithelium
The line between - Hilton's white line
102
What is the blood supply to the anal canal?
Upper 2/3 = superior rectal artery
| Lower 1/3 = inferior rectal artery
103
What is the embryological origin of the upper 2/3 of the anal canal?
Endoderm
104
What is the embryological origin of the lower 1/3 of the anal canal?
Ectoderm
105
What does the epidermis originate from embryologically?
Ectoderm
106
What are the main type of cells that make up skin?
Keratinocytes
107
What are the non-keratinocytes that are present in skin?
Melanocytes
Langerhans cells
Merkel cells
108
What are keratinocytes?
Epithelial cells that contain keratin
109
Keratinocytes have immune properties how?
They produce:
Interleukins
Interferons
Growth Factor
110
What are the 5 epidermal layers?
```
Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum
```
111
What is the Stratum Basale?
A single layer of mitotically dividing cells attached to the basement membrane - these cells produce the keratinocytes
112
What are melanocytes developed from?
Melanoblasts which originate in neural crest
113
What do melanocytes do?
Produce melanin - transfer to keratinocytes
114
What are Langerhans cells in skin developed from?
haemopoetic bone marrow cells
115
What is the role of Langerhan's cells in the skin?
They are antigen-presenting cells so have immune function
116
What is the role of merkel cells?
Neuroendocrine cells - act as mechanoreceptors and mediate tactile tension
117
What does the dermis originate from embryologically?
Mesoderm
118
Where do the primordial germ cells originate from?
Epiblast
119
Where do the germ cells migrate to?
Genital ridge
120
The arrival of germ cells causes the epithelium of the genital ridge to proliferate and form what?
Primitive sex chords
121
What signals the development of MALE genitals?
Y chromosome has gene called the Sex Determining Region which codes for a protein called Testis Determining Factor
122
What happens in the absence of the Testis-Determining Factor?
Female development occurs
123
In males what do the Primitive sex cords form?
Testis cords (medullary cords)
124
When the Testis cords break up what do they form?
Rete testis
125
What is the name of the fibrous connective tissue that forms under the epithelium of the genital ridge?
Tunica Albuginea
126
What do the remaining excretory tubules of the mesonephric system give rise to?
Efferent ducts that link the rete testis and Mesonephric duct
127
What structures does the Mesonephric duct form?
Epididymis
Vas deferens
Seminal vesicles
Ejactulatory duct
128
The seminferous tubules are formed at birth. True or false?
False - the testis cords remain solid until puberty
129
Where do the testis form?
Posterior abdominal wall - they descend into the scrotum before birth
130
What happens to the Mullerian Duct in males?
It degenerates
131
What causes the Mullerian Duct to degenerate in males?
Anti-Mullerian hormone
132
What cells produce the Anti-Mullerian Hormone?
Stertoli cells
133
What do the urethral folds form in males?
Scrotum
134
What substance mediates the majority of male genital development?
Testosterone
135
What happens to the primitive sex cords in females?
They dissociate into cell clusters
136
Second generation cords form called cortical cords what happens to them?
They split into isolated cell clusters and surround the germ cells - form follicular cells
137
What happens to the mesonephric duct and excretory tubules in females?
They degenerate
138
What does the Mullerian ducts form?
1) Uterine tubes
2) Uterus
3) Cervix
4) Upper Vagina
139
What is the differentiation of the Mullerian duct stimulated by?
Oestrogen
140
Where does the oestrogen come from in embryonic development?
1) Ovaries
2) Mother
3) Placenta
141
What does the urogenital sinus form in females?
1) Lower vagina
2) Labia Majora
3) Labia Minora
4) Clitoris
142
What do the urethral folds form in females?
Labia Majora
143
What is the name for the production of spermatozoa?
Spermatogenesis
144
What is the name for the extention of peritoneum that covers the testes anteriorly?
Tunica vaginalis
145
What is the role of stertoli cells?
1) Nurture sperm development
| 2) Form blood-testis barrier
146
Why is there a blood testis barrier?
It is to protect the developing sperm from the immune system as the sperm do not have the same genetic information as somatic cells in the body
147
What do the seminiferous tubules drain into?
Rete testis
148
What is another name for the foreskin?
Prepuce
149
Why are the testes outside of the body?
To keep the testes at a lower temperature than the body - this is needed for their development
150
What is the mechanism for keeping the testes cooler than the body?
Heat exchange in the Pampiniform plexus - this is where the returning blood in the veins cools the warmer blood coming in the testicular artery
151
What happens in meiosis I to the genetic material?
The homologous chromosome pairs are seperated
152
What happens in meiosis II to the genetic material?
The duplicate sister chromatids
153
Spermatogonia produce two types of daughter cells, what happens to them?
Type A remain outside blood-testis barrier and produce more daughter cells
Type B differentiate into primary spermatocytes
154
What is formed after meiosis I?
2 Secondary spermatocytes
155
What is formed after meiosis II?
4 spermatids
156
What is spermiogenesis?
The transformation of spermatids into spermatozoa
157
What happens in spermiogenesis?
The spermatids sprout a tail and they discard their cytoplasm
158
How many sperm are made per gram of testis per second?
300-600
159
What is the blood-testis barrier formed by?
Tight junctions between the basement membrane under the sertoli cells
160
How long does it take for spermatogenesis to be completed?
64 days
161
What are the efferent tubules?
Ciliated ducts that collect spermatazoa from the rete testes and transport them to the epididymis
162
What is semen made up of?
- Seminal vesicle fluid
- Prostatic secretions
- Sperm
- Bulbourethral fluid
163
Semen also contains fructose, why?
To provide energy for the sperm so they can be mobile
164
Semen contains prostaglandins, why?
To stimulate female peristaltic contractions
165
Why is meiosis important in gamete formation?
1) Prevents polyploidy - where there is two (or more) copies of the genetic information
2) Increases genetic variability
166
When does meiosis I begin in female gamete formation?
In utero before 12 weeks
167
When does meiosis I end?
Puberty - it arrested at metaphase 1 until puberty occurs
168
When does meiosis II occur?
Puberty
169
When does meiosis II end?
Fertilization - it is arrested until fertilization
170
At what point do male and female gonads differentiate?
Week 6
171
What is the hormonal state before puberty?
1) Low pulsatility amplitude of GnRH and secretion
| 2) Low levels of FSH, LH and gonadal sex steroids
172
What happens to the relevant hormones at puberty?
1) Increased amplitude of GnRH and GHRH
2) Increased levels of FSH, LH and sex steroids
3) Increased levels of growth hormone
173
What are primordial follicles?
They are single oocytes surrounded by a layer of epithelial cells (granulosa cells)
174
What stimulates follicular development?
Cyclic FSH secretion
175
What happens in the formation of the primary follicle?
1) Granulosa cells proliferate
2) Oocyte enlarges
3) Stroma organised into connective tissue
4) Zona pellucida forms directly around oocyte
176
What happens in the formation of the secondary follicle?
1) Formation of antrum - filled with follicular fluid
2) Connective tissue differentiates into theca interna and theca externa
3) Oocyte supported in antrum by stalk of granulosa cells
177
What is the name of the stalk of granulosa cells that supports the oocyte?
Cumulus oophorus
178
What is the name of a mature follicle?
Graafian follicle
179
What happen in the formation of the Graafian follicle?
1) Ovum surrounded by thick zona pellucida
2) Layer of granulosa cells surround oocyte known as corona radiata
3) There is a basal lamina
4) There is a developed theca interna and externa
180
What happens to the follicle after ovulation?
It converts into a corpus luteum
181
What does the corpus luteum do?
Secretes progesterone and oestrogen
182
What is the fate of the corpus luteum?
It persists if pregnancy occurs, if not it regresses
183
What happens to the corpus luteum after it regresses?
Forms a corpus albicans - eventually resorbed or replaced by ovarian stroma
184
What are the four segments of the uterine tube?
1) Intramural
2) Isthmus
3) Ampulla
4) Infundibulum
185
What is the intramural part of the fallopian tube?
The part that is inside the uterine wall
186
What is the isthmus part of the fallopian tube?
A thick-walled part - narrow
187
What is the ampulla part of the fallopian tube?
An expanded part of the Fallopian tube
188
What is the infundibulum of the fallopian tube?
A trumpet-shaped opening to the peritoneum which has fimbrae
189
What are the layers of the fallopian tube lining?
1) Mucosa
2) Muscularis
3) Serosa
190
Describe the structure of the mucosa of the fallopian tube
Thrown into branching folds - plicae
| has three types of cells: Secretory, ciliated and intercalated
191
Describe the structure of the muscularis of the fallopian tube?
Inner circular layer with outer longitudinal layer
192
What is the serosa of the fallopian tube?
Connective tissue covered by mesothelium
193
What are the three layers of the uterus?
1) Endometrium
2) Myometrium
3) Serosa
194
The endometrium is composed of two layers, what are they?
1) Stratum basalis
| 2) Stratum compactum and stratum spongiosum (functional layer)
195
The endometrium undergoes a proliferation phase, what is it?
Where glands proliferate, become tortuous and show mitotic activity
There is no luminal secretions
Stomal cells are spindled and compact
196
What is the proliferation phase stimulated by?
Oestrogen
197
The endometrium undergoes a secretory phase, what happens in the early phase?
sub-nuclear vacuoles form
198
What happens in the mid part of the secretary phase?
Intraluminal secretions occur, glands become more rounded and there stroma oedema
199
What happens in the late part of the secretory phase?
The glands become elongated and there are more luminal secretions
Stroma has spiral arterioles
200
What stimulates the secretory phase?
Progesterone
201
What happens in the menstrual phase?
Stomal haemorrhage occurs and theres stromal and glandular fragmentation
202
What initiates the menstrual phase?
Progesterone withdrawl
203
Describe the myometrium
Three layers (poorly defined)
Inner longitudinal
Middle circular
Outer longitudinal
204
What is the endocervix?
The part of the cervix past its enterance
205
What is the ectocervix?
The entrance to the cervix
206
What is the endocervix lined by?
Simple ciliated columnar epithelium
207
What is the ectocervix lined by?
Stratified non-keratinized squamous epithelium
208
What is the vagina lined by?
Stratified non-keratinizing squamous epithelium
209
What are the three layers of the vagina?
1) Mucosa
2) Muscularis
3) Adventitia
210
What is the labia minora lined by?
Mostly stratified non-keratinizing squamous epithelium
211
What is the labia majora lined by?
Stratified keratinizing squamous epithelium
212
What are the two main glands in the female genitalia?
1) Bartholin's gland - mucus secreting
| 2) Minor vestibular glands - mucus secreting
213
What occurs to the female genitalia in menopause?
There is ovary, endometrium, cervix and vagina atrophy
214
How long is the menstrual cycle normally?
28 days
215
Between what days does menstruation take place in the cycle?
Day 1-7 (lasts between 3 and 7 days)
216
What happens in days 8-11 of the menstrual cycle?
The endometrium thickens in preparation for an egg
217
What day does ovulation take place in the cycle?
Day 14
218
What happens between days 18-25?
Corpus lueum fades away if pregnancy has not occurred
219
What happens at days 26-28 in the menstrual cycle?
The endometrium detaches from the uterus wall and leads to menstruation
220
What two mechanisms are responsible for sperm transport in the female reproductive tract?
1) Sperm motility
| 2) Contractions of the female reproductive tract
221
How long can sperm be "stored" in the human female reproductive tract?
5 days
222
What process do sperm have to go through before they can fertilize the ovum?
Capacitation
223
What happens in capacitation?
1) Sperm head membrane is changed so it can fuse more easily
| 2) The sperms motility increases
224
What is the Zona Pellucida?
A glycoprotein layer that surrounds the oocyte and is vital in binding spermatozoa for fertilization
225
What is a pronuclei?
The nucleus of a sperm of oocyte in the process of fertilization before fusion has taken place - they are still haploid
226
What is the process syngamy?
1) Male and female pronuclei migrate to centre
2) Haploid chromosomes pair and replicate
3) Pronuclear membranes breakdown
4) Mitotic spindles form
5) 46 chromosomes line at the equator
227
How long after fertilization does the first cleavage occur - division?
Approx. 24 hours
228
What is responsible for developmental control prior to the 4-8 cell stage?
Maternally derived stores of RNA laid down in oogenesis
229
What is responsible for development control at the 4-8 cell stage and onwards?
The embryonic genome - at this stage it is activated
230
At day 4 compaction occurs, what does this involve?
1) Cells flatten - maximising intracellular contacts
2) Tight junctions form
3) Polarisation of the outer cells occurs
231
At what stage does differentiation start to occur?
Day 5
232
At day 6 the oocyte undergoes "hatching" what does this refer to?
The embryo hatching from the zona pellucida
233
What two groups of layers have you got a differentiation?
1) Trophoectoderm
| 2) Inner mass cells
234
What do the inner mass cells comprise of?
1) Extra embryonic membrane
2) Extra embryonic mesoderm
3) Extra embryonic endoderm
4) Embryonic ectoderm
5) embryonic mesoderm
6) Embronic endoderm
235
What forms the chorian and placenta?
1) Chrorioic ectoderm (from trophoectoderm)
| 2) Extra embryonic mesoderm
236
What forms the amnion?
Extra embryonic membrane and mesoderm
237
What forms the yolk sac?
Extra embryonic mesoderm and endoderm
238
What forms the fetus?
Embryonic ectoderm, mesoderm and endoderm
239
What is the metabolic and biosynthetic activity and nutritional requirements at early cleavage?
Low - nutritional requirements are simple (low glucose and non-essential amino acids
240
What is the metabolic and biosynthetic activity and nutritional requirements at the blastocyst stage?
High - nutritional requirements are complex (high glucose and essential and non-essential amino acids and vitamins
241
What provides the exogenous nutrients to the blastocyst?
1) Cumulus cells
2) Fallopian tube secretions
3) Uterine secretions
242
What is the implanation window of the blastocyst?
19-22 days
243
What causes attachment of the blastocyst to occur?
1) Apical surface of endometrium has integrins
2) Trophoblastic cells also express intergrins
Integrins are adhesion molecules
244
What does the trophoblast differentiate into?
1) Cytotrophoblast
| 2) Syncytiotrophoblast
245
What does the synctiotrophoblast do?
Penetrates the basal lamina and erodes endometrial stroma - this erodes the vessels forming blood filled lacunae
246
What happens in the decidual reaction phase?
Progesterone primed endometrial stromal cells adjacent to blastocyst differentiate into metabolically active secretory cells - decidual cells
247
What prevents the embryo being attacked by the mother immune system?
Leucocytes in the endometrial stroma release interleukin-2 which prevents maternal recognition
248
What is the role of hCG?
Sustains early pregnancy, supports the corpus luteum and therefore progesterone production
249
In addition to supporting the development of sperm what else do sertoli cells do?
Phagocytose faulty sperm
250
Describe Leydig cells' function, appearance and location?
1) Cluster of cells in the interstitium between tubules
2) Produce testosterone
3) Large amount of SER
4) Reinke's crystals
251
What are the tubuli recti?
They connect the seminiferous tubules to the rete testis
252
Describe the rete testis
1) Irregular anastomosing channels
2) Cuboidal epithelium
3) Microvilli and cillia
253
What are the three parts of the epididymis?
Head, body and tail
254
What is the function of the epididymis?
Storage and maturation of sperm
255
What is the epithelium of the epididymis?
Pseudostratified columnar epithelium with stereocilia
256
What is the structure of the Vas deferens?
Pseudostratified columnar epithelium with 3 layers of muscle
257
What happens to the prostate in aging?
Stroma and glands both undergo hyperplasia
258
What is another name for Bulbourethral glands?
Cowper's
259
What do the bulbourethral glands do?
Secrete lubricating mucus
260
What are the parts of the uterus?
Body
Fundus
Neck
Os - opening
261
What is the uterus supported by?
1) Broad ligament
2) Round ligament
3) Cardinal ligaments
4) Rectouterine ligament
5) Vesicouterine ligament
262
What is a transvaginal ultrasound used for??
To assess thickness of the uterus lining and the ovaries - involves insertion of probe
263
What is a sonohysterography?
A more in-depth investigation into the uterus using ultrasound and injected fluid
264
What are the benefits of ultrasound?
1) Real-time imaging
2) Minimally invasive
3) Not believed to be harmful
265
What happens in a hysterosalpinography?
1) Catheter inserted into uterine cavity
2) Contrast injected
3) Contrast flows into fallopian tubes
4) X-ray image obtained
266
When are scans usually taken in pregnancy?
1) 12 weeks
| 2) 20 weeks
267
What is the purpose of the 12 week scan?
To assess date of pregnancy: looks at heart beat, crown-rump length, number of fetuses and nuchal translucency
268
What is the purpose of the 20 week scan?
To assess for any abnormailites
269
What happens if possible abnormalities are found?
1) Second scan
2) Councelling
3) Further investigations
270
When are MRI's NOT done in pregnancy ?
First trimester
271
When do the exocrine functions of the pancreas begin?
After birth
272
When do the endocrine functions of the pancreas begin?
10-15 weeks
273
Is the pancreas retroperitoneal or intraperitoneal?
Retroperitoneal
274
What cells carry out exocrine functions?
Acinar cells
275
What cells carry out endcrine activity?
Islets of Langerhans
276
Which type of cells is significantly dominant in the pancreas?
Exocrine
277
What doe the alpha cells in the islets of Langerhans produce?
Glucagon
278
What do the beta cells in the islets of Langerhans produce?
Insulin
279
What do the delta cells in the islets of Langerhans produce?
Somatostatin
280
Describe briefly the process of insulin secretion from the beta cells?
1) Glucose enters through GLUT2 transporter
2) Glucose metabolism occurs - ATP formed
3) Potassium channels close - depolarises membrane
4) Calcium channels open
5) Insulin secretory granules fuse with membrane and release insulin
281
What feature shows that insulin has been produced endogenously?
Presence of C peptide
282
What is proinsulin?
Contains A and B chains of insulin joined by C peptide (disulphide bridges hold the two chains together)
283
The release of insulin is biphasic, what does this mean?
1) First phase is rapid release of stored hormone
| 2) Second phase is slow as it is the release of newly synthesised hormone
284
Describe the mechanism in which insulin acts of muscle and fat cells
1) Insulin binds to insulin receptor on cell
2) Intracellular signalling takes place
3) GLUT4 vesicle mobilized to plasma membrane
4) GLUT4 allows glucose to move into cell
285
What is the short-term response to high glucose?
Glycogenesis
286
What is the long-term response to high glucose?
Lipogenesis
287
What is the short-term response to low glucose?
Glycogenolysis - breaking down glycogen
288
What is the long-term response to low glucose?
Gluconeogenesis - make glucose
289
Where are the primary glucose sensors?
Pancreatic islets
290
Where are glucose sensors found other than pancreatic islets?
Medulla
Hypothalamus
Carotid bodies
291
What is the gut hormone that stimulates insulin release?
Incretins
292
Where does glucose go in the body?
40% liver
| 60% periphery (mainly muscle)
293
What supplies the anterior pituitary with blood?
Through portal venous circulation from the hypothalamus
294
What are the hormones released by the hypothalamus?
1) GHRH
2) GnRH
3) TRH
4) Dopamine
295
What hormones are released from the anterior pituitary galnd?
1) GH
2) LH
3) FSH
4) ACTH
5) TSH
6) Prolactin
296
What are three main issues that can occur from a pituitary tumour?
1) Pressure on nerves - particularly optic nerves
2) Pressure on normal pituitary - hypopituitarism
3) Functioning tumour - secretes hormones
297
What would happen if the pituitary tumour pressed on the optic chiasm?
Bitemporal hemianopia
298
What does the posterior pituitary gland originate from?
Neural tissue - large numbers of glial-type cells
299
What two hormones are released by the posterior pituitary gland?
1) Vasopressin
| 2) Oxytocin
300
What is the function of vasopressin?
Controls water reabsorption
301
What is the function of oxytocin?
1) Expression of milk from the glands to the nipples
| 2) Contractions of the uterus - initation of labour
302
Where in the posterior pituitary gland is vasopressin released from?
Supraoptic nuclei
303
Where in the posterior pituitary gland is oxytocin released from?
Paraventricular nuclei
304
The hormones released by the posterior pituitary are formed in the hypothalamus - how do they get to the posterior pituitary gland?
In the axoplasm of the neurons
305
What triggers vasopressin release?
Osmoreceptors in hypothalamus - day to day
Baroreceptors in brainstem and great vessels - in emergency
306
What is the condition in which you lack vasopressin?
Crainial diabetes insipidus
307
What is the condition in which you are resistant to vasopressin?
Nephrogenic diabetes insipidus
308
What is oxytocin stimulated by in women?
Suckling
309
What leads to the release of thyroid hormones from the thyroid gland, starting at hypothalamus?
1) Hypothalamus releases Thyrotropin-releasing hormone
2) This stimulates the release of Thyroid-stimulating hormone from the anterior pituitary gland
3) this stimulates the release of the thyroid hormones
310
What are the hormones produced by the thyroid gland?
1) Thyroxine (T4)
2) Triiodothyronine (T3)
3) Calcitonin
311
What is stored in the follicles of the thyroid gland?
Thyroglobulin
312
What is the actions of thyroid hormones?
1) Increasing metabolism
2) Growth and development
3) Increased catecholamine effect
313
What is the action of calcitonin?
Works to reduce calcium levels by:
1) Inhibiting osteoclasts
2) Stimulating osteoblast activity
3) Inhibits calcium reabsorption in renal tubules
314
What effect does calcitonin have that is the same as PTH?
It inhibits phosphate reabsorption in the renal tubules
315
What cells produce calcitonin?
C cells or parafollicular cells
316
What is produced in the Zona glomerulosa of the adrenal glands?
Mineralocorticoids - Aldosterone
317
What is produced in the Zona fasciculata of the adrenal gland?
Glucorticoids - cortisol
318
What is produced in the Zona reticularis?
Androgens
319
What is produced in the medulla of the adrenal gland?
Catecholamines - e.g. adrenaline
320
What is the name for the part of the adrenal gland that contains the Zona glomerulosa, fasciculata and reticularis?
Adrenal cortex
321
What is the function of ACTH?
It stimulates corticosteroid synthesis
322
What are the actions of glucocorticoids?
1) Increased glucose mobilisation
2) Maintenance of circulation - vascular tone, salt and water balance
3) Immunomodulation - dampens immune response
323
How are glucocorticoids transported?
1) Corticosteroid-binding globulin (CBG) (90%)
2) Albumin-bound (5%)
3) Free (5%)
324
What affect do glucocorticoids have on hypothalamus and pituitary gland?
Inhibit CRH and ACTH release - negative feedback
325
What happens in the plasma and urine when there is endocrine salt loss?
Plasma: Sodium = low, potassium = high
Urine: Sodium = high, potassium = low
326
What stimulates androgen production in the adrenal glands?
ACTH (not gonadotrophins like in gonads)
327
What is different about the adrenal medulla?
It is part of the autonomic nervous system
328
Which is produced in greater amounts in the adrenal medulla, adrenaline or noradrenaline?
Adrenaline - 80%
| Noradrenaline - 20%
329
What does endocrine mean?
"Within" - this is where the glands secrete into the blood stream
330
What does exocrine mean?
"Outside" This is where the glands secrete substances into ducts which transport to site of action
331
What is the other name for the anterior pituitary gland?
Adenohypophysis
332
What is the other name for the posterior pituitary gland?
Neurohypophysis
333
What inhibits prolactin secretion?
Dopamine
