SUGER Flashcards
What is neurourology?
Management of neuropathic bladder, bowel and sexual function
What are the types of incontinence?
Stress incontinence, urge incontinence, retention with overflow
What is the function of the urinary tract ?
Collect the urine, store it and void it when socially appropriate
What are the key factors of filling in a normal bladder?
Continence, sensation of bladder volume and receptive relaxation
What are the key factors of voiding in a normal bladder?
Voluntary initiation and emptying completely
What are the consequences of rtinary tract dysfunction?
Infections, bladder stone and upper tract injury
What in the function of the upper urinary tract?
Prevention of reflux and active peristalsis
What are the urethral sphincters?
Distal urethral sphincter (smooth muscle, intrinsic striated sphincter and extrinsic strained sphincter) and urethral sphincter, which is only used during ejaculation
What is the rhabdosphincter made of?
Intrinsic striated distal urethral sphincter. It is a slow twitch striated muscle.
What are the local afferents in the bladder?
The guarding reflex
Where does the Onuf’s upper motor neurone come from?
The motor cortex, it travels in the cortico-spinal tracts
What is the bladder made of?
It is composed of multiple segments of smooth muscle with their associated ganglia. Each segment exhibits spontaneous activity (micromotions)
Can the bladder be denervated?
No
What does the sacral micturition centre control?
Parasympathetic control of the bladder, with C fibre local afferents. Causes reflex bladder contractions
What do A delta fibres do?
Control normal sense of bladder fullness
What is sympathetic control of the bladder?
The bladder has receptive relaxation, the bladder neck during ejaculation and the smooth muscle sphincter
What does the pontine micturition centre do?
Possible medial (micturition) and lateral (storage) centres. It is the motor centre for the autonomic control of the lower urinary tract
What happens in the periaqueductal gray do?
It has the visceral and somatic control centre for the lower urinary tract. It receives A delta fibre input and communicates with conscious centres
How does the cerebral cortex affect the bladder?
It receives sensation and voluntary initiation
How does the midbrain affect the bladder?
It had the periaqueductal gray and the pontine micturition centre. It controls coordination and completion of voiding
What are the spinal reflexes involved in passing urine?
The reflex bladder contraction in the sacral micturition centre (coordination of micromotions); guarding reflex in Onuf’s nucleus
What does neuropathic mean?
Disorder of function due to nervous system dysfunction
What does atrophy mean?
Decrease in size or wasting away of a body part or tissue
What makes up the urinary system?
Kidneys, ureters, urinary bladder and urethra
What is the function of the kidney?
To filter the blood
What is the function of the ureter?
To transport the urine to from the kidney to the urinary bladder
What is the function of the urethra?
Conduct the urine from the bladder to the exterior atmosphere
How much of the cardiac output do the kidneys receive?
About 1/5th
What is the blood supply of the kidneys?
The renal arteries
Where do the renal arteries arise from?
Directly from the abdominal aorta
What hormones do the kidneys produce?
Erythropoietin and renin
What is the function of erythropoietin?
Controls red blood cell production
What is the function of renin?
It regulates water and salt concentrations
What are the two divisions of the kidney?
A pale coloured outer cortex and the darker regoins of central medullary tissue
How many medullary pyramids does each kidney contain?
10-15
What does the cortex of the kidney contain?
All the glomeruli, the convoluted (coiled) parts of the proximal and distal tubes, and the proximal parts of the collecting ducts
What do the medullary pyramids of the kidney contain?
The straight portions of the proximal and distal tubules, the loops of Henle and teh distal parts of the collecting ducts
What enters and leaves the kidney hilum?
The renal artery and vein
What does the renal artery divide into?
5 or 6 main branches that give off arcuate arteries at the corticomedullary junction. From these arise the interlobular arteries
What is the path of the interlobular arteries?
The interlobular arteries penetrate the cortex at regular intervals diving the cortex into lobules. They give off afferent arterioles that supply the glomeruli
Where is the blood filtered in the kidney?
The glomeruli
How does the filtered blood leave the glomeruli?
Via the efferent arterioles and passes through thin walled vesseles between the tubules. Here it acquires fluid and ions recovered by the nephrons.
What do the efferent arterioles in the kidney drain into?
They drain into the arcuate veins for return to the systemic circulation
What blood vessel supplies the medulla of the kidney?
Near the cortico-medullary junction the arcuate arteries give off straight arteries that penetrate deep into the medulla
What is the path of the blood entering the kidney to be filtered?
First it goes to the glomeruli to be filtered. The primary filtrate is passed to the rest of the nephron for selective re-absorption of certain solutes
What does the glomerulus consist of?
A parallel array of fenestrated capillaries ensheathed by specialised endothelial cells called podocytes
Where is the filtration barrier of the kidney?
It is the basement membrane between the endothelial cells of the capillaries and the podocytes of the epithelium
Where are mesangial cells and what do they do?
They are between the coiled loop of the glomerular. They are important in forming the matrix
Where are the specialised renin-producing cells in the kidney?
In the wall of the afferent arteriole
Where is the macula densa of the kidney?
It is a specialised palisade of cells in a segment of distal tubule alongside the glomerulus
What does the glomerular tuft made up of?
Capillary loops supported by podocytes. It is surrounded by the urinary space that separates it from the glomerular capsule
What is the function of the mesangial cells?
They are responsible for providing the overall framework of the glomerulus
What is the first segment of the tubule of the nephron?
The proximal tubule. It is the most highly coiled segment. The cells have a prominent brush border and complex invaginations of their baso-lateral membrane
What takes place in the proximal tubules?
Extensive re-absorption of the filtrate. Na+, glucose and amino acids are actively transported in. Proteins and polypeptides are transported by endocytosis and lysozymes in their break them down.
What are the sections of the loop of Henle?
A thick straight descending portion, a thin loop and a thick ascending portion
Which loops of Henle have the longest and most penetrating thin loops?
The ones belonging to nephrons whose glomeruli lie close to the cortico-medullary junction
What does the ascending portion of the loop of Henle do?
It retains (is impermeable to) water although chloride and sodium are re-absorbed. This results in the production of a dilute filtrate but an interstitium that is hyper tonic
What does the descending portion of the loop of Henle do?
It has a low permability to ions and urea but is highly permeable to water so water is reabsorbed
What is the path of the distal tubule?
It follows on from the loop of Henle. It returns to the medulla to the cortex and then to the vascular pole of its own glomerulus.
How does aldosterone affect the distal tubules?
It increases sodium and bicarconate reabsorption and potassium and H+ excretion. This means the urine is acidic
List two important proteins that normally pass from the blood into the primary filtrate but are then reabsorbed:
Almost any small negatively charged protein can enter the glomerular filtrate but will be reabsorbed. Proteins such as albumins and Hb are too large to enter the filtrate
What is the difference between the proximal and distal tubules?
The proximal tubule is normally longer and more tightly coiled than the distal tubule
Are proximal or distal tubules more numerous type of tubules within the cortex?
The proximal tubule appear more numerous than those of the distal tubule
Where is the collecting duct in the nephron?
It is the final part of the nephron
What is the path of the collecting duct?
It starts in the cortex and filtrate from the distal tubule passes first into collecting tubules and thence into larger collecting ducts
How are medullary rays formed?
The collecting tubules from several nephrons coalesce to form larger ducts that pass into the medulla and from visible streaks known as medullary rays
Do collecting ducts have lots of mitochondria?
They have a high concentration of mitochondria
How does ADH affect the kidneys?
ADH increases the permeability of the collecting ducts cells and as a consequence water is re-absorbed to interstitium thereby concentrating the urine
What does the juxta-glomerulus apparatus consist of?
It consists of the afferent and efferent arterioles, the macula densa and specialised cells of the glomerular matrix known as lacis cells
What in the kidney produces renin?
Cells in the walls of the afferent arteriole are adapted to produce renin that appears as granules in the cytoplasm
What does renin do?
Renin when released, catalyses the conversion of angiotensin to angiotenis 1, the first step in the stimulation of aldosterone release by the suprarenal glands
Where is angiotensinogen produced?
In the liver
Where is angiotensin 1 converted to angiotensin 2?
Mainly in the lungs
What does angiotensin 2 do?
It stimulates the release of aldosterone by glomerular cells in the cortex of the suprarenal gland
Where does aldosterone?
Cells of the distal tubules and collecting ducts where this hormone promotes the reabsorption of the sodium ions and water and thereby concentrates the urine and conserves body fluid
What is urothelium?
The ureters, bladder and most of the urethra are lined by a pseudo-stratified epithelium often referred to as urothelium
What happens to bladder epithelium when it is full?
As the bladder fills with urine the epithelium is stretched and the apparent number of layers of cells decreases
What are the layers of the ureter?
It has a star shaped lumen. The epithelial tube is surrounded by two helical layers of smooth muscle.
How do the muscle fibers of the ureter vary?
Toward the bladder the muscle fibres become predominantly longitudinal in orientation
What are the three points where the ureter is sharply constricted?
(1) at it’s origin in the pelvis of the kidney; (2) as it passes into the true pelvis anterior to the sacro-iliac joint; (3) as it enter the postero-inferior side of the bladder
How does the ureter prevent reflux of urine?
The compression of the ureter as it passes obliquely through the muscular wall of the bladder prevents reflux
What is the wall of the bladder made of?
It is composed of thick bundles of smooth muscle with no preferred direction except at the neck where the urether where it acts ac a sphincter
What is the bladder neck sphincter made of?
3 distinct layers of smooth muscle. The innermost longitudinal layer projects inferiorly and turns transversely to form a sphincter around the prostatic urethra (male) and the external meatus (female)
What is the main type of nerve supply to the bladder?
Parasympathetic from the sacral outflow. Sympathetic mainly affects the blood vessels of the bladder
Is the urethra longer in the male or female?
Male
What are the parts of the male urethra?
There are prostatic, membranous, bulbous and pendulous parts
How is blood flow of the glomerulus regulated?
By constriction of the afferent and efferent arterioles
Is the proximal convoluted or the distal convoluted tubule more tightly coiled?
Apart from the straight portions of these tubules, the proximal tubule is more tightly coiled than the distal tubule.
What is the result of the proximal convoluted tubule being more coiled than the distal convoluted tubule?
There are more transverse and fewer oblique sections through the proximal tubules than through the distal tubules
How do the loops of Henle differ in length?
Nephrons with glomeruli close to the medulla have long loops of Henle that project deep into the medulla. Ones close to the surface of the kidney have short loops that project to the outer medulla
Why is the wall of the ureter composed mainly of smooth muscle rather than of fibrous connective tissue?
The musclular wall of the ureter undergoes peristaltic contraction that helps to conduct the urine to the bladder
What causes the bladder to contract during micturition?
When the external sphincter of the bladder is relaxed (sympathetic stimulation) and detrusor muscle of the bladder wall contracts (parasympathetic stimulation)
Which glands drain into the prostatic urethra?
Most genital glands. Including the prostate, the seminal vesicles and the deferent duct.
What glands drain into the penile urethra?
The bulbo-urethral glands and other smaller mucous glands
What are the constituents of the male reproductive tract?
The testis, the epididymus, the vas deferens and the urethra
Where does the reproductive tract join the urinary tract?
Within the prostate gland and seminal fluid is expelled via the prostatic, membranous and penile urethra
What is the tunica albuginea?
A thick, dense collagenous capsule that encloses each testis
What do the seminiferous tubules drain into?
They drain into a network of channels (rete testis) that deliver sperm to the epididymis.
Where are and what is the function of Leydig cells?
They are between the seminiferous tubule in clumps and they produce testosterone
What is an exocrine gland?
pour’ secretions through a duct to site of action e.g. exocrine pancreas - amylase, lipase
What is an endocrine gland?
glands ‘pour’ secretions into blood stream e.g. thyroid, adrenal, beta cells of pancreas
What is in the major endocrine system?
Pituitary; Thyroid; Parathyroid; Adrenal; Pancreas; Ovary; Testes
Why do we have an endocrine system?
communication for multi-cellular organisms; allows integration of whole body physiology; rapid adaptive changes; chronic maintenance of metabolic environment
What is the feedback loop for the endocrin system?
It is mostly negative feedback
What is another name for the pituitary gland?
Hypophysis
How is the pituitary gland connected to the hypothalamus?
By the pituitary sta;l
Where does the pituitary gland sit?
In a bony cavity called the pituitary fossa
What are the two distinct portions of the pituitary gland?
The anterior (adenohypophysis)and the posterior (neurohypophysis)
What stimulates the adrenal gland to release cortisol?
The pituitary gland releases ACTH which stimulates the adrenal gland
What creates thyroxine?
The pituitary gland secretes TSH which stimulates the thyroid gland to secrete thyroxine
What regulates the production of prolactin?
Dopamine
What does prolactin do?
It is involved in lactating. It is usually in low levels because dopamine stops the production of it
What are the causes of high blood prolactin levels?
pituitary stalk compression; pituitary stalk transection; pituitary tumour; dopamine antagonist drugs - anti- emetics, anti-psychotics
What stimulates growth hormone secretion?
Starvation – especially protein deficiency; Hypoglycaemia, or low concentration of fatty acids in the blood; Exercise; Excitement; Trauma; Increases during the first two hours of deep sleep
Is growth hormone secreted in a pulsatile pattern?
Yes, which is why you have growth spurts
Is the thyroid vascular?
Yesss! very much so!
What is the action of thryoxine?
increases metabolic rate; excess is catabolic - muscle breakdownl important in brain maturation (cretinism - congenital hypothyroidism)
How does thyroid hormone work?
Acts by binding thyroid hormone receptor; Receptor/hormone complex binds DNA; Alters gene transcription
Where is the parathyroid gland?
Behind the thyroid gland. There are four of them
What is the function of the parathyroid gland?
Control serum calcium levels; Secrete parathyroid hormone (PTH); Parathyroid glands have calcium receptors that monitor circulating levels of calcium
What does parathyroid hormone do?
Causes resorption of calcium from bone; increases absorption of calcium from gut; PTH is secreted normally when calcium levels fall
What is hyperparathyroidism?
Excess secretion of parathyroid hormone
What are the cells of the pancreas and what do they secrete?
Insulin - Beta cells of islets of Langerhans
Glucagon - Alpha cells
Somatostatin - delta cells
What controls the levels of glucose?
Insulin (decreases it) and glucagon (increases it) but mainly insulin affects it
What endocrine glands make steroids?
The adrenal gland, the ovary and the testes
How do steroids work?
Act by binding cytoplasmic receptors and then binding DNA; Change gene transcription
How are hormones transported to the posterior pituitary?
Hormones are transported to the posterior pituitary in the axoplasm of the neurons
Where is the posterior pituitary originited from?
Originates from Neuro tissue – large numbers of Glial-type cells
What two hormones do the posterior pituitary secrete?
Vasopressin (Antidiuretic hormone – controls water secretion into urine); Oxytocin – expression of milk from the glands of the breasts to the nipples; promotes onset of labour.
Where in the posterior pituitary is vasopressin released from?
Primarily from supraoptic nuclei
Where in the posterior pituitary is oxytocin released from?
Primarily from paraventricular nuclei
What and where are the secreting cells of the posterior pituitary?
Secreting Cells are large neurons, magnocellular neurons located in the supraoptic and paraventricular nuclei of the hypothalamus
Do oxytocin and vasopressin have short or long half lives?
Short so they have very precise regulation
What happens to vasopressin if there are large blood volumes?
The baroreceptors detect blood volume increase and trigger the release of vasopressin
Where are the vasopressin receptors?
V1a - vasculature
V2 - renal collecting tubules - reabsorption of water V1b - pituitary
What controls the release of vasopressin?
osmoreceptors in hypothalamus - day to day baroreceptors in brainstem and great vessels - emergency
What are the main extracellular ions?
Na+, Ca2+, Cl-, HCO3-
What are the main intracellular ions?
K+, Mg2-, PO3- and proteins
If you are thirsty, what happens to vasopressin secretion?
It increases so less water is excreted in the urine
Where are the vasopressin receptors in the kidney?
In the collecting duct, the final bit of the kidney. If they are bound to vasopressin then you can’t pass urine into the bladder
How do you measure osmolality?
Measured by an osmometer - by freezing point. The higher the salt concentration the lower the freezing point
What is osmolality?
Concentration per kilo - in plasma very similar to osmolarity - but concentration slightly different as approx 6% of volume made up by lipids and protein
Is size or number of particles the determinant of osmolality?
size of particle not important, number is important - i.e one molecule of larger protein albumin same effect as Na+
What ions affect the osmolality?
sodium, potassium, chloride, bicarbonate, urea and glucose are all present at high enough concentrations to affect osmolality
Name some exogenous solutes that affect osmolality:
alcohol, methanol, polyethylene glycol or manitol
Is oxytocin synthesised in both sexes?
Synthesized in both sexes, but it only has well-recognized physiological effects only in women
What does oxytocin do?
stimulates milk let down; stimulates contraction of myometrium (100X more potent that AVP); 200X less active at the V2 receptor compared to AVP
Where are oxytocin receptors?
Receptors on myometrium, myoepithelial cells of the breast
What is the oxytocin pathway?
Gq, PLC, Ca2+signaling pathway
What is the anterior pituitary supply?
The anterior pituitary has no arterial blood supply but receives blood through a portal venous circulation from the hypothalamus
What does the anterior pituitary regulate?
The gonads and cortisol levels
What is the function of cortisol?
Cortisol is an essential hormone for maintaining energy metabolism, growth and for fertility
How does growth hormone affect the liver/
It releases IGF 1 which increases cartilage formation and cartilage growth
What is tubuloglomerular feedback?
where chemical changes in the tubules feedback to alter the glomerular filtration rate.
What is the kidney blood flow rate?
1L/min
What is the normal GFR?
100ml/min
What is the normal urine flow rate?
1mL/min
What is an acid and a base?
Base - a proton acceptor
Acid - a proton donater
What is the titratable acidity?
Quantity of base to bring pH to 7.4 (10-40 mEq H+ per day)
Where is the hormone receptor for thyroid hormones?
Nucleus
What is WT1?
Genes involved in the development of the kidney
What is PKD1?
Genes involved in maintenance of normal structure of the kidney
What is COL4A5?
Genes involved in the function of the glomerulus
What is CLCNKB?
Genes involved in the function of the collecting system
What is acidemia?
Low blood pH
What is alkalemia?
High blood pH
What is the anion gap?
Difference between measured anions and cations.
= [Na+] + [K+] – [Cl-] – [HCO3-]
Normal is 10-16
What are the causes of metabolic acidosis?
Failure of H+ excretion (renal failure); Excess H+ load (lactic acidosis or ingesting acids); HCO3- loss (diarrhoea)
What are the causes of metabolic alkalosis?
Alkali ingestion; Gastrointestinal acid loss (Vomiting); Renal acid loss (hyperaldosteronism)
What is stress incontinence?
Leakage on coughing, straining; Weak sphincter
What is urge incontinence?
Leakage with urgency; Bladder overactivity
What is urinary retention with overflow?
Continuous dribbling
Where does meiosis of the spermatozoa occur?
In the seminiferous tubules
What is type A of spermatogonia daughter cells?
They remain outside blood-testis barrier & produce more daughter cells until death
What is type B spermatonogia daughter cells?
differentiate into primary spermatocytes; cells must pass through blood testis barrier to move inward toward lumen - new tight junctions form behind these cells; meiosis I -> 2 secondary spermatocytes; meiosis II -> 4 spermatids
What is spermiogenesis?
The transformation of spermatids into spermatozoa (sprouts tail and discards cytoplasm to become lighter)
What forms the blood-testis barrier?
Tight junctions between and basement membrane under sertoli cells.
What is contained within the head of the spermatozoa?
A nucleus contains haploid set of chromosomes; acrosome contains enzymes that penetrate the egg; basal body
What is in the tail of the spermatozoa?
Midpiece contains mitochondria around axoneme of the flagellum (produce ATP for flagellar movement); principal piece is axoneme surrounded by fibers; endpiece is axoneme only and is very narrow tip of flagellum
What is syngamy?
Fusion of the gametes in fertilisation
What is aposition?
Synchronisation of the embryo and the endometrium
What is the role of hCG?
Essential to sustain early pregnancy; Supports the corpus luteum (progesterone production); Interacts with the endometrium via specific receptors
What are the three layers of the uterus?
The endometrium, the myometrium and the serosa
What is in the male reproductive system?
Testis; Epididymis; Vas Deferens; Prostate; Seminal Vesicle; Cowper’s Gland; Penis
What is parturition?
The birth process; Successful transition from intra-uterine to extra-uterine life
What is the function of the uterine cervix?
Protects the fetus during development
What is the uterine cervix made of?
Mainly collagen and ground substance with glycosaminoglycans; Collagen has cross-links which increase tensile strength
What is cervical ripening?
Growth and remodelling of the cervix prior to labour
What stimulates cervical ripening?
Occurs under influence of placental hormones and relaxin throughout gestation
What produces prostaglandins?
All uterine tissue can
What is menopause?
cessation of menstruation
What is climacteric menopause?
The period around the menopause and at least the first year after it.
What is the cause of menopause?
Depletion of primordial follicles
What does the epidermal skin barrier consist of?
Corneo-desmosomes; lipid bilayers; convalently-bound lipids; heratohyaline granules; desmosomes
How do protease inhibitors prevent allergens getting through the skin?
The stop degradatory proteases from breaking down corneodesmosomes so allergens can’t enter through the skin
What is urinary tract composed of?
The kidneys, the ureters, the bladder and the urethra
Are the kidneys retroperitoneal or intraperitoneal?
Retroperitoneal
What are the levels of the kidneys?
T12 - L3
Which kidney is lower down?
The right is lower down than the left because it is pushed down by the liver.
What are the parts of the kidney?
It has an inner medulla and an outer cortex
What is the inner medulla of the kidney made out of?
It is made of around 20 upside down pyramids and an inner pelvis containing fat and the urine collecting system.
What is the renal cortex made of?
It is composed of renal corpuscle and the proximal and distal tubules.
Where and what is a medullary ray?
In the renal cortex. It is a collection of loop of Henle tubules and collecting ducts that originate from the nephrons in the outer part of the cortex
Where are the tubules of the loop of Henle, the tubules of the collecting duct and blood vessels?
In the renal medulla
What is the renal pelvis?
It is a space which urine drains into. It is continuous with the collecting ducts proximally and the ureters distally.
What is the blood supply to the kidney?
The renal artery, which branch directly off the abdominal aorta at L1
What does the renal artery split into?
Anterior and posterior renal arteries -> interlobular arteries -> arcuate arteries -> intralobular arteries -> arrerent arterioles -> renal corpuscle capillaries
What parts of the nephron are in the renal cortex?
The proximal and distal convoluted tubules and the renal corpuscles
What parts of the nephron are in the renal medulla and medullary rays?
The loop of Henle and the collecting ducts
What is the function of the renal corpuscle?
It filters the blood
What is the function of the proximal convoluted tubule?
It reabsorbs solutes
What is the function of the loop of Henle?
It concentrates urine
What is the function of the distal convoluted tubule?
It resorbs more water and solutes
What is the function of the collecting duct?
It resorbs water and controls acid, base and ion balance
What is the glomerulus of the kidney?
The capillary tuft within the Bowman’s capsule
What is within the renal corpuscle?
The glomerulus and the Bowman’s capsule
What is the capillary tuft in the renal corpuscle?
It is a tuft of convoluted capillaries with fenestrated walls, it is supported by smooth muscle containing mesangial cells
Embryologically, how is the pancreas formed?
At the junction of foregut and midgut 2 pancreatic buds (dorsal and ventral) are generated and eventually fuse to form pancreas
When does the pancreas start to function?
·Exocrine functions begins after birth
·Endocrine (hormone) functions from 10-15 weeks
Which cells in the islet of Langerhans are most common?
Beta cells
Name the region which seminiferous tubules immediately drains into?
Rete Testis
Which cells produce testosterone?
Leydig cells
Where does sperm maturation and storage take place?
The epididymis
Where does fertilisation of an ovum most frequently happen?
The uterine tubes
Innervation of the erectile tissue of the penis is by…..
Efferent parasympathetic sacral spine roots
Describe the four main endocrine axis from the pituitary?
ACTH - adrenal glands - cortisol
TSH - thyroid glands - thyroxine
LH/FSH - ovaries/testis - Oestrogen/testosterone
GH - liver - IGF-1
What is EPO and why do endurance athletes illegally use it?
Erythropoietin - hormone that increases red blood cells production, raising the haematocrit and thus increasing O2 carrying capacity
What type of cells secrete CCK and secretin and where are they located?
APUD cells in the mucosa of the GI tract and pancreas. They reduce gastrin and increase pancreas secretion
What is the role of glucagon?
It stimulates the conversion of glycogen to glucose and gluconeogenesis
What does TSHR do?
It regulates follicular cell function
What does thyroid peroxidase?
The enzyme which oxidises iodide to iodine
What does thyroglobulin do?
A large globular protein of tyrosine made in follicular cells and transported into colloid. It is then reabsorbed by follicular cells to make hormones
What does thyroxine do?
Increases cardiac function, increases heart rate, increases ventilation rate, increases basal metabolic rate,
What is the order in which follicles develop?
Primordial follicle (FSH & LH stimulate development)
Primary follicle
Secondary follicle (First meiotic division complete)
Graafian follicle (Second meiotic division starts)
Ovulation
Corpus luteum
Corpus albicans (if no fertilisation)
What are the stages of fertilisation?
Day 1: fertilisation
Days 2-3: cleavage
Day 4: compactation
Day 5: cavitation & differentiation
Day 5/6: expansion
Day 6: hatching
What is spermatogenesis?
Spermatocyte goes through meiosis to make haploid spermatids
What is spermiogenesis?
Transformation of spermatids to spermatozoa. The spermatids discard excess cytoplasm and grow tails
What is acidaemia?
Abnormal acidity of the blood
What is alkaleamia?
Abnormal basicity of the blood
What is the blood supply of the anterior pituitary?
It has no arterial blood supply. It has a portal venous circulation from the hypothalamus.
How does somatostatin affect growth hormone?
Somatostatin is released when growth hormone levels are high. It inhibits release of growth hormone from the anterior pituitary.
How does dopamine affect prolactin levels?
Dopamine has a negative effect on prolactin production
Does the posterior pituitary synthesise hormones?
No, it only stores and releases them
How is thyroxine transported?
Bound to albumin or other proteins
What is the function of the pineal gland?
Secretes melatonin and contributes to diurnal rhythm and ‘promotes’ sleep
What hormones does the placenta produce?
Progesterone, oestrogen, somatomammotrophin, human chorionic gonadotrophin
What hormones are involved in the initiation of labour?
Oxytocin, PGF2-a
What is the difference between osmolality and osmolarity?
Osmolarity is a measure of solute per litre of solution, osmolality is per kilogram of solvent (doesn’t change with temperature and pressure)
What is the function of cortisol?
It is a fight/flight response so turns off all body processes that aren’t essential to life eg.growing/inflammation
How does cortisol affect bones?
Decreases bone formation; Inhibits differentiation of osteoblasts and blocks vitamin D; Reduces calcium absorption and increases excretion; excess results in osteoporosis
How does corticol affect the vascular system?
Maintains the responsiveness of arterioles to pressers; maintains blood volume by decreasing vascular permeability; excess results in hypertension.
How does cortisol affect the kidneys?
It inhibits both secretion and the action of ADH; deficiency may lead to water retention.
How does cortisol affect the CNS?
It modulates perception and emotion; effects wakefulness; excess can result in insomnia
How does cortisol affect the immune system?
Inhibits the generation of inflammatory mediators (prostaglandins, vasodilators); Decrease cytokine production; Blocks cell mediators; Block recruitment of neutrophils; Inhibits fibroblast function.
What happens if there is a change in skin pH?
Denaturation of desmosomes -> breakdown of skin junctions -> barrier failure
