SUGER Flashcards
What is the opening and exit of the inguinal canal?
Opening = deep inguinal ring, exit = superficial inguinal ring
What are the boundaries of the inguinal canal?
anterior – aponeurosis of superior oblique
posterior – transversalis fascia
roof – transversalis fascia, internal oblique, transversus abdominis
floor – inguinal ligament (pubic tubercle -> anterior superior iliac crest)
What are the contents of the inguinal canal?
Spermatic cord or round ligament
Genital branch of genitofemoral artery
Ilioinguinal nerve
What is the difference between a indirect and direct herniation at the inguinal canal?
Indirect – congenital, through deep inguinal ring
Direct – abdominal weakness, through posterior inguinal canal wall
Why do hernias often occur at the inguinal canal?
No abdominal muscles present (I think, double check)
Go through the 2 coverings of the testicles
Tunica vaginalis: • External layer derived from peritoneum • Covers anterior surface and sides of testes Tunica albuginea: • Fibrous capsule enclosing testes • Penetrates parenchyma -> lobes
Go through the route spermatozoa takes starting at the semniferous tubules
o Spermatozoa production in seminiferous tubules -> rete testes -> efferent tubules -> epididymis
Function and anatomy of the epididymis
Stores sperm for 50 days
Head -> coiled body -> tail connects to vas deferens
What innervates the testicles?
Testicular plexus
What is the arterial supply to the testicles?
Paired testicular arteries via the inguinal canal
What is the venous drainage in the testicles?
Left testicular vein -> left renal vein
Right testicular vein -> inferior vena cava
Describe the anatomical position of the kidneys
o Retroperitoneal, T12-L3, R kidney lower than L kidney
What are the layers around the kidney?
Kidney capsule
Perirenal fat
Renal fascia (kidney and suprarenal glands covered)
Pararenal fat
Go through the deeper layers of the kidney and include the function and a basic description of each
o Cortex: Space for renal arterioles and venules Production of EPO Divides medulla into renal pyramid o Medulla: Functional units of kidney – nephrons Form renal pyramids Apex of pyramid – minor calyx Minor calyx -> major calyx = urine collection o Pelvis: Collects urine from major calices Drains urine into ureter
What is the arterial supply to the kidneys?
Renal arteries arise directly from abdominal aorta – L1-L2
Renal arteries -> hilum -> segmental branches -> interlobar -> arcuate -> interlobular -> afferent arterioles -> glomerulus
What is the venous drainage of the kidneys?
o Venous drainage – renal veins -> inferior vena cava
Describe the shape of the supra-renal glands
o R adrenal gland = pyramidal, L adrenal gland = semi-lunar
What are the layers of the adrenal cortex?
Zona glomerulosa
Zona fasciculate
Zona reticulate
What does the adrenal cortex secrete?
Corticosteroids and androgens
What does the adrenal medulla secrete?
Catecholamines from chromaffin cells
What are the layers of the adrenal glands?
Cortex and medulla
What is the arterial supply to the adrenal glands?
Superior adrenal artery – inferior phrenic
Middle adrenal – abdominal aorta
Inferior adrenal – renal arteries
What is the venous drainage of the adrenal glands?
Right adrenal vein -> inferior vena cava
Left adrenal vein -> left renal vein
What are the 3 parts of the ureter?
Abdominal, pelvic, intramural (in bladder)
Where are the narrowing of the ureter?
Ureteropelvic junction – renal pelvis -> ureter
Bifurcation of common iliac artery
Oblique entrance of ureter into bladder wall
Go through the branches of the abdominal aorta
o Inferior phrenic arteries – T12– diaphragm
o Coeliac trunk – L1 – stomach, liver, duodenum
o Superior mesenteric artery – lower L1 – jejenum, ileum, ascending and transverse colon
o Middle suprarenal arteries – L1 – adrenal glands
o Renal arteries – L1 and L2 – kidneys
o Gonadal arteries – L2 – testicles and ovaries
o Inferior mesenteric artery – L3 – transverse, descending and sigmoid colon, rectum
Name the muscles in the posterior abdominal wall
Quadratus lumborum – lateral
Psoas major – medial
Iliacus – fan shaped below quadratus lumborum
o Iliacus and psoas major combine to form iliopsoas – hip flexion
What innervates the muscles of the posterior abdominal wall?
o Posterior wall muscles innervated by lumbar plexus – T12-L4
What is the function of the bladder?
Store and expel urine
What is the structure of the bladder?
Apex – connection to umbilicus by medial umbilical ligament
Body
Fundus – contains trigone, smooth walled orifice = entrance of ureters
Neck – joins bladder to urethra
What are the muscles in the bladder?
Detrusor – contracts during micturition
Internal urethral sphincter – smooth muscle fibres in male, female functional sphincter
External urethral sphincter – voluntary skeletal muscle relaxes during micturition
What’s the arterial supply to the bladder?
Internal iliac artery
What is the sympathetic supply to the bladder?
detrusor relaxation, parasympathetic supply = detrusor contraction
Describe the parts of the vulva in the female genitalia
Mons pubis – superior pad of fat
Labia majora – hair bearing folds
Labia minora – non-hair bearing folds
Clitoris – erectile corpus cavernosa tissue (genital tubercle)
What is the function, histological layering and arterial supply of the vagina?
Function – transport to and from uterus for baby, menstrual fluid, semen
Histological – stratified squamous epithelium, elastic lamina propria, fibromuscular layer, adventitia
Arterial supply – uterine and vaginal arteries from internal iliac
Go through the anatomy of the cervix
Ectocervix -> external os -> endocervical canal -> internal os
What is the function of the cervix?
Connects vagina and uterus, maintains uterine sterility
What are the 3 layers, the 3 parts and arterial supply (for cervix too) of the uterus?
3 parts – fundus, body (blastocyst implantation), cervix
3 layers – endometrium -> myometrium (muscular) -> perimetrium
Arterial supply of cervix and uterus – uterine arteries
Go through the fallopian tubes
Fimbriae -> infundibulum -> ampulla (fertilisation) -> isthmus
Which layers cause peristaltic contractions in the fallopian tubes?
Inner ciliated mucosa and muscular layer
What are the basic layers of ovaries?
Surface, cortex (primordial germ cells), medulla (neurovascular)
What is the arterial supply to the ovaries and fallopian tubes
ovarian arteries from abdominal aorta
What are the ligaments in the abdominal female genitalia?
Broad ligament – sheet of peritoneum covering uterus and ovaries
Ovaries:
• Ovarian – connects ovary to uterus
• Suspensory – connects ovary to lateral abdominal wall
Uterus:
• Round ligament – passes through inguinal canal, connects uterus and labia majora
What are the parts of female genatalia?
Vulva, vagina, cervix, uterus, fallopian tubes, ovaries, ligaments
What are the parts of the male genitalia?
Penis, scrotum, spermatic cord, prostate gland, seminal vesicle and ejaculatory duct
What is the general route semen takes in the penis?
Root -> body -> glans
General anatomy of the soft tissues
L and R crus and bulb in root -> L and R corpus cavernosa and corpus spongiosum (contains urethra and glans)
Muscles in the penis
- Bulbospongiosus – bulb of penis – expulsion in micturition
* Ischiocavernosus – L and R crus of penis – squeezing blood into penis
Describe the fascia in the penis?
- Deep fascia = superficial layer = continuation of perineal fascia
- Tunica albuginea – capsule covering individual parts of penis
Describe the ligaments in the penis
- Suspensory – connects erectile tissue to pubic symphysis
* Fundiform – continuation of linea alba, attaches to pubic symphysis
What is the arterial supply and venous drainage of the penis?
Arterial supply
- Dorsal and deep penile arteries, bulbourethral arteries
- Branches of internal pudendal -> internal iliac
Venous drainage
- superficial and dorsal veins of the penis
Parasympathetic or sympathetic stimulation for ejaculation?
Sympathetic
What does the scrotum contain?
testes, epididymis and spermatic cord
What is the dartos muscle?
Layer of smooth muscle which contracts the scrotum for heat loss
What is the arterial supply of the scrotum?
Superior and inferior scrotal tissue supplied by the external and internal pudendal artery
Go through the spermatic cord
Deep inguinal ring -> superficial inguinal ring -> scrotum
What are the structures in the spermatic cord?
- Testicular artery and vein (pampliform plexus)
- Genital branch of genitofemoral nerve
- Vas deferens
What are the 3 zones of the prostate gland and what is its arterial supply?
3 zones – central, peripheral, transitional
Arterial supply – prostatic arteries -> internal pudendal arteries
What produces semen and how much of this fluid makes up ejaculate?
o Seminal vesicle produces semen – fluid makes up 70% of ejaculate
What is the ejaculatory duct?
confluence of seminal vesicle and prostatic duct and vas deferens
What are the 2 hiatus in the pelvic floor?
Urogenital and rectal
What are the muscles in the pelvic floor?
Levator ani – puborectalis (continence), pubococcygeus, ileococcygeus
Coccygeus
What makes up the pelvic floor?
Muscles and fascia
What are the contents and boundaries of the urogenital triangle?
o Boundaries – pubic symphysis and pelvic ischial tuberosities
o Contains most of the important UG stuff – male/female genitalia
What is the GFR?
o Filtration volume per unit time – 125ml/min
o Measured GFR = conc of M in urine x urine flow rate/conc of M in plasma - creatinin
o Renal clearance – volume of plasma from which a substance is completely removed by the kidney
<125ml/min – freely filtered and partially reabsorbed
>125ml/min – freely filtered and excreted
0ml/min – freely filtered and completely reabsorbed (glucose)
What is hydrostatic pressure?
P -> out of vessel
What is oncotic pressure?
O -> into vessel
Equation for GFR
o GFR = (PGC – PBS) – (OGC – OBS) x KF
Factors affecting GFR
Afferent dilation/efferent constriction -> increased PGC -> increased GFR
Afferent constriction/efferent dilation -> decreased PGC -> decreased GFR
What is autoregulation
Increase blood flow in afferent arteriole -> stretch of wall -> smooth muscle contracts -> arteriolar constriction
Systemic circulation BP change doesn’t affect renal circulation
What is tubuloglomerular feedback?
Macula densa detect NaCl -> release prostaglandins -> granular cells release renin
What is the filtration barrier?
o Podocytic foot processes, basement membrane and capillary endothelium
o Small and +ve charged molecules can cross filtration barrier
o Glomerular basement membrane has -ve charge -> proteins can’t cross barrier
Discern between osmolarity and osmolality
• Osmolarity – concentration of solute in litres vs osmolality – concentration of solute in kg
What is the structure of the nephron?
o Glomerulus – basic filtration unit
o Proximal convoluted tubule – bulk reabsorption
o Loop of Henle – urinary dilution
o Distal convoluted tubule – selective reabsorption
o Collecting duct – like distal tubule
Go through the proximal convoluted tubule and symporters, antiporters as well as bicarbonate reabsorption
o Basolateral Na/K pump establishes conditions for mass reabsorption
o Glucose and phosphate absorbed with sodium – symporter
o Sodium absorbed as H+ excreted – antiporter
o Bicarb reabsorption:
1. H+ combines with bicarb to form carbonic acid
2. Converted to carbon dioxide and water by carbonic anhydrase
3. Carbon dioxide diffuses into cell -> carbonic acid reformed
4. Bicarb pumped into capillary through basolateral membrane
Go through the Loop of Henle
o Descending limb = water absorption, ascending limb = solute absorption
o Vasa recta reabsorbs water in descending limb -> higher osmolarity down descending limb
o Vasa recta reabsorbs solutes in ascending limb -> decreasing osmolarity up ascending limb
o Top of loop of Henle = low osmolarity, bottom of loop = high osmolarity
o Creates conditions for selective reabsorption in collecting duct
o NKCC2 transporter – reabsorption of Na, K and Cl (ROMK = K excretion)
Go through the distal convoluted tubule
o Continues urine dilution – reabsorption of Na, impermeable to water
o NCC transporter – Na and Cl
Go through the collecting duct
o Surrounded by hypertonic medullary interstitium – set up by loop of Henle
o Water impermeable, selective Na absorption, selective K and acid secretion
Go through a principle cell
Contains ENaC – epithelial sodium channel
K excretion
Aldosterone = more ENaC channels = inc Na reabsorption and K excretion
ADH -> V2 receptors -> aquaporins in apical membrane -> increased water permeability
Go through a intercalated cell
Acid secretion
ATPase pumps out H ions – by-product of bicarb production in renal cell
K/H antiporter
Ammonia diffuses into tubular fluid -> combines with H to form ammonia
What are the hormonal effects on the renal system?
o Parathyroid hormone:
Blocks phosphate reabsorption in proximal convoluted tubule
Increases calcium reabsorption every else
o Atrial natriuretic peptide:
Glomerular arteriole dilation -> increased GFR
Increased vasa recta blood flow
Affects NCC transporter– decreased sodium reabsorption in distal convoluted tubule
Inhibits renin secretion – RAAS system
o Angiotensin 2, aldosterone and vasopressin all increase blood volume levels by increasing water reabsorption at the kidneys
What are the 3 urinary buffers?
H ion secretion, phosphate buffer and ammonia buffer
Go through the phosphate buffer
Most common, impermeable to apical membrane
HPO42- + H+ -> H2PO4-
Go through the H ion secretion buffer
Allows reabsorption of bicarb in proximal tubule (H + HCO3- -> H2CO3 -> CO2 + H2O)
Daily acid load secretion – buffers required
Go through the ammonia buffer
Adaptive response to acid load -> synthesised from glutamine
NH3 diffuses into tubular fluid -> NH4+ impermeable to apical membrane
Proximal convoluted tubule -> reabsorbed in loop of Henle -> intercalated disc in collecting duct
Law of mass action = principle that the rate of a chemical reaction is proportional to the concentrations of the reacting substances
What happens during respiratory acidosis?
o Hypoventilation = hypercapnia = equilibrium shifts to right = more H+ o Renal compensation: Increased H+ secretion Increased bicarb production Increased ammonia secretion
What happens during respiratory alkalosis?
o Hyperventilation = hypocapnia = equilibrium shifts to left = less H+
o Renal compensation:
Decreased H+ secretion
Increased bicarb secretion
What happens during metabolic acidosis?
o Excess acid production or decreased bicarb concentration
o Respiratory compensation:
Low pH stimulates chemoreceptors
Increased ventilation -> decreased Pco2
What happens during metabolic alkalosis?
o Vomiting = acid loss
o Respiratory compensation:
High pH stimulates chemoreceptors
Decreased ventilation -> increased Pco2
Go through the RAAS system
• RAAS system:
- Body sodium levels decrease -> blood pressure decrease
- Macula densa cells detect low sodium and low arteriolar BP -> renin release from juxtaglomerular apparatus
- Renin cleaves angiotensinogen from liver into angiotensin 1
- Angiotensin converting enzyme from lungs converts angiotensin 1 -> angiotensin 2
Where are macula densa cells found?
JGA (I think double check)
What are angiontensin 2 functions?
aldosterone release from adrenal cortex – zona glomerulosa
Vasoconstriction of efferent arteriole
ADH release from posterior pituitary
Increased proximal tubular sodium reabsorption - cotransport
What is aldosterone’s function?
Increased K secretion in collecting duct
Increased eNaC channels in principal cells
Go through the ADH system
o Vasopressin synthesised in supraoptic nuclei of hypothalamus -> stored in posterior pituitary
o Hypothalamic osmoreceptors detect increased osmolarity -> ADH release
o ADH functions:
Increase in water permeability in distal convoluted tubule and collecting duct – aquaporin 2 channels
Increase in urea permeability in collecting duct
Increased sodium absorption in ascending loop of Henle -> increased osmolaric counter-current exchange
What is the general shape of each adrenal gland?
o R adrenal gland = pyramidal, L adrenal gland = semilunar
What’s the layered structure of adrenal glands?
Zona glomerulosa – mineralocorticoids – aldosterone
Zona fasciculata – glucocorticoids – cortisol
Zona reticularis – androgens – DHEA -> testosterone
Medulla – catecholamines - adrenaline
What is derived from cholosterol?
o Steroid hormones produced in adrenal glands
What are the receptors in the adrenal glands?
Mineralocorticoids only act on mineralocorticoid receptors
Glucocorticoids act on mineralocorticoid and glucocorticoid receptors
Androgen only act on androgen receptors
What is the action of cortisol?
Released in response to stress and low blood glucose levels
Increases gluconeogenesis and fat/protein metabolism
What is the action of adrenaline?
Catecholamines released from adrenal medulla – peptide hormones
Functions – gluconeogenesis, lipolysis, increased heart rate
Alpha receptors in smooth muscle – vasoconstriction/dilation
Beta receptors:
• Beta 1 – amylase secretion
• Beta 2 – bronchodilation
• Beta 3 – lipolysis in adipocytes
What are the functions of skin?
o Mechanical barrier and waterproofing
o Regulates temperature and electrolytes
o Sunlight – UV protection and vit D production
o Sensory and immune organ
What are the epidermal layers of skin?
o Corneum – dead keratinised cells
o Lucidum – dead cells containing keratohyalin
o Granulosum – keratohyalin + protein envelope, cells begin dying
o Spinosum – keratin fibres and lamellar bodies
o Basale – mitotic cells migrate up to spinosum
What are keratinocytes?
o Skin cells – 95% of epidermis
o Nucleated epithelial cells containing keratin – fibres move through desmosomes
What is the dermis layer of the skin?
o Papillary dermis – rete ridges, type 3 collagen, ground substance + fibroblast
o Reticular dermis – type 1 collagen, well organised and elastic fibres
What does subcutaneous tissue have an abundance of?
Adipocytes
Why does healthy skin have a pH of 5.5?
this allows the proteases to remain on the skin thereby enabling balance of new cells from the basal layers of the epidermis (desquamation)
What causes skin flare ups?
• Skin flare ups are caused by allergens which penetrate the skin where they’re met by lymphocytes which release chemicals to induce inflammation:
o Red skin: dilation of blood vessels
o Itchy skin: stimulation of nerves
o Dry skin: skin cells leaking
What is the cause of increasing pH?
• Less water retention in the corneocytes will mean pH will increase which results in damage to the skin barrier since corneodesmosomes become damaged by the increased pH
In acne, how is skin irritation and inflammation induced?
• In acne, hypercornification of the stratum corneum results in adherent cells blocking the entrance to hair follicles -> increased production of greasy sebum -> sebum trapped in narrowed hair follicle -> sebum stagnates in anaerobic conditions in the pit of the hair follicle -> allows propionic bacteria acnes to multiply there -> irritation and inflammation
What is the skin barrier essentially?
o Lipid lamellae above cells - corneocytes connected by corneodesmosomes
Examples of positive and negative feedback loops in the body
• Positive feedback loop = oxytocin, negative feedback = pretty much all the other hormones
Function of the hypothalamus
o Homeostasis – thirst, sleep, temp regulation
o Controls endocrine function via pituitary
Functions of the hormones produced by the hypothalamus
Thyrotropin releasing hormone – stimulates TSH release
Corticotropin releasing hormone – stimulates ACTH release
Gonadotrophin releasing hormone – stimulates LH and FSH release
Growth hormone releasing hormone – stimulates GH release
Dopamine – inhibits prolactin release
What is the blood supply to the anterior pituitary?
o No arterial supply -> portal venous supply from hypothalamus (superior hyphoseal)
What are the hormones released from the anterior pituitary and their function?
Thyroid stimulating hormone (TSH) – stimulates thyroid to release thyroxine
Follicle stimulating hormone (FSH) – stimulates ovarian follicle growth
Luteinising hormone (LH) – stimulates ovulation
Adrenocorticotrophic hormone (ACTH) – glucocorticoid and androgen production
Growth hormone (GH) – growth, metabolism, bone mass
Prolactin – stimulates lactation
Go through a hypothalamus-pituitary feedback example
o Hypothalamic input – stress, diurnal rhythm, cytokine release
o Hypothalamus releases CRH -> anterior pituitary
o Anterior pituitary releases ACTH -> zona fasciculus of adrenal cortex
o Cortisol released from adrenal glands
o Cortisol inhibits release of ACTH and CRH – negative feedback
Function the posterior pituitary
o No production of hormones -> storage of hypothalamic hormones
Divisions of the posterior pituitary and their functions
o Supraoptic nucleus:
Produces vasopressin
Vasopressin function – increase renal fluid reabsorption (aquaporins)
o Paraventricular nucleus:
Produces oxytocin
Oxytocin function – positive feedback system during labour
Which cells are involved in the exocrine activity in the pancreas?
• Exocrine activity – acinar cells, make up 98% pancreatic cells
Go through the Islets of Langerhans in relation to cell types
• Islets of Langerhans: o Alpha cells: Glucagon synthesis Glucagon function – utilises glucose stores o Beta cells: insulin secretion Insulin function - decreased hepatic gluconeogenesis, increase glucose storage o Delta cells – somatostatin secretion
Go through insulin secretion
- Glucose enters beta cells via GLUT2 transporter
- Glucokinase metabolises glucose -> glycolysis and Kreb produces ATP
- ATP closes K channel -> no efflux of K -> depolarisation of cell
- Depolarisation causes influx of Ca -> exocytosis of insulin
- Endogenous insulin has C peptide attached – exogenous is free insulin
Go through insulin action
- Insulin binds to insulin receptor on target cell
- Increased exocytosis of GLUT4 vesicles to cell membrane -> more GLUT4 vesicles in cell membrane
- Increased glucose uptake through GLUT4 receptors
What is the fasting state in terms of glucose regulation?
o Glucose comes from liver:
Gluconeogenesis – pyruvate from glucose-alanine cycle
Hepatic glycogen stores utilised - glucagon
o Low insulin levels – glucose supplied to brain and RBC
What is the feeding state in terms of glucose regulation
o Rising glucose levels increases insulin synthesis, decreases glucagon synthesis
o Glucose travels to liver and muscles – converted to glycogen storage
o Excess glucose converted to fat in adipocyte
What is hyperglycaemia?
• Hyperglycaemia -> inhibition of glucagon release
What is hypoglycaemia?
• Hypoglycaemia -> inhibition of insulin release
What’s the location, structure, blood supply and venous draniange of teh thyroid gland?
• Anatomy:
o Location:
C5-T1
Inferior to thyroid cartilage
Wraps around cricoid cartilage and superior tracheal rings
o Structure – 2 lobes separated by isthmus
o Blood supply (paired arteries):
Superior thyroid artery – external carotid artery
Inferior thyroid artery – subclavian
o Venous drainage -> jugular vein
What are the cell types found in the thyroid gland?
o Follicular cells: Surround colloid to form follicles Produce T3 and T4 o C cells: Parafollicular cells Secrete calcitonin
e synthesis
- Thyroid stimulating hormone released from anterior pituitary
- Na/I symporter increase iodine uptake
- Thyroglobulin iodinised – catalysed by thyroperoxidase
- Thyroglobulin + tyrosine -> thyroxine (T3 and T4)
Name the thyroid hormones
o Triiodothyronine (T3) – biologically active hormone o Thyroxine (T4) – de-iodinised in peripheral tissues to form T3, most abundant
How are the thyroid hormones carried in the blood?
o T3 and T4 carried in bloodstream bound to albumin and thyroxine binding protein
What is the function of the thyroid? What is the function of thyroxine?
- Thyroid function – absorption of iodine
* Thyroxine function – conversion to T3, metabolic regulation
What hormonal changes occur during pregnancy?
o Human chorionic gonadotrophin: stimulates ovarian oestrogen and progesterone production o Oestrogen: regulates progesterone levels prepares uterus + lactating breasts o Progesterone: builds up endometrium inhibits uterine contraction o Prolactin: increases milk-producing cells o Relaxin: Limits uterine activity Involved in cervical ripening o Oxytocin: Caring reproductive behaviour Cause uterine contractions during labour o Prostaglandins: Tissue hormones that initiate labour
Name 4 maternal adaptions
CV, respiratory, veins and skin
Go through the respiratory maternal adaptions
Increased inspiratory volume
Increased breathing rate
Go through the CV maternal adaptions
Increased cardiac output
Decreased peripheral resistance -> decreased BP
Increased uterine blood flow
Increase plasma and RBC volume
Go through the venous maternal adaptions
Growing uterus -> presses on IVC
Increased lower limb venous pressure -> varicose veins
Go through the skin maternal adaptions
Linea nigra – dark line between umbilicus and pubic symphysis
Stretch marks at site of maximal growth
What induces the initiation of labour?
o Stress -> CRH release -> ACTH release -> cortisol release -> oestrogen release
o Oestrogen release -> inhibits uterine progesterone release -> uterine contractions
o Prostaglandins (PGF2a) and relaxin (from ovaries) relax walls of cervix -> dilation
o Baby pushing onto cervix -> oxytocin release -> uterine contractions (positive FB)
What happens during cervial ripening at labour?
o Growth and remodelling of cervix prior to labour o Hormones involved – placental: Prostaglandins Relaxin Oxytocin
Go through the phases that occur in the endometrium during menstruation and pregnancy
Proliferative phase: • Stimulated by oestrogen • Glands proliferate and show mitotic activity Secretory phase: • Stimulated by progesterone • Glands secrete into lumen of uterus • Reduces smooth muscle capabilities of uterus • Spiral arteries increase blood flow Menstrual phase: • Progesterone stimulation removed • Stromal haemorrhage and fragmentation
What is the general structure of the myometrium?
Inner longitudinal
Middle circular
Outer longitudinal
What is the structure and function of the placenta?
Umbilical cord:
• 2 umbilical arteries
• 1 umbilical vein
Maternal side – villous tree structures = blood/nutrient supply
o Functions:
Metabolism – synthesises glycogen and fatty acids for energy
Transport – gas and nutrients, water, glucose, hormones, most molecules
What are the hormones and their functions released from the placenta?
Human chorionic gonadotrophin -> luteinising hormone
Human chorionic somatomammotrophin – mammary development
Human chorionic thyrotrophin and corticotrophin – thyroxine and cortisol
Oestrogen and progesterone – proliferative and secretory endometrium
Relaxin – cervical ripening and dilation
What happens during follicular development at birth and puberty?
o Birth:
40,000 primary oocytes in primordial follicles
Arrested in prophase of meiosis 1 until puberty
o Puberty:
FSH and LH released by anterior pituitary
Primordial follicle -> meiosis 1 -> secondary follicle -> meiosis 2
Graafian follicle contains secondary oocyte – haploid nucleus
Polar body produces during meiosis 1 and meiosis 2
Go through the 4 stages in the menstrual cycle in detail
o Follicular phase:
1. Gonadotrophin releasing hormone released from hypothalamus
2. FSH released from ant pituitary – proliferation of granulosa follicular cells
3. LH released from ant pituitary – proliferation of granulosa cells in follicles
4. Oestrogen released from granulosa cells – stimulates endometrium growth
5. At low levels oestrogen inhibits release of FSH and LH from ant pituitary
6. Inhibin released from granulosa cells – inhibits ant pituitary
o Ovulation:
1. Oestrogen production reaches threshold – no longer negative feedback
2. LH surge causes weakening in follicle wall -> mature ovum released
o Luteal phase:
1. FSH and LH cause follicle to degrade into corpus luteum
2. Corpus luteum produces high amounts of progesterone and some oestrogen
3. Progesterone stimulates endometrium growth – ready for blastocyst
4. Corpus luteum suppresses FSH and LH production from ant pituitary
o Post luteal:
1. Implantation – embryo produces human chorionic gonadotrophin hormone which preserves corpus luteum and endometrium
2. No implantation – low FSH and LH levels cause corpus luteum atrophy which stops progesterone production and menstruation occurs
Go through fertilization
- Capacitation – sperm prepares for fertilisation by destabilising membrane
- Sperm binds to corona radiata -> reaches zona pellucida
- Acrosome bursts -> digests through glycoprotein matrix
- Cortical granules release -> hardening of zona pellucida -> no sperm entry
- Sperm enters oocyte cytoplasm and fuses with ovum nucleus
Go through the 6 step process of implantation
1. Syngamy: • Day 1 • Chromosomes align in preparation for mitosis 1 2. Cleavage: • Day 2-3 • Mitotic division occurs • Totipotent stem cells 3. Compaction: • Day 4 • Cells flatten • Tight gap junctions between cells 4. Cavitation + expansion: • Day 5 • Blastocyst formation 5. Hatching: • Day 6-8 • Blastocyst hatches from zona pellucida 6. Implantation
Other names for the Wolffian and Mullerian ducts
Mesonephric and paramesonephric ducts
What is the Wolffian duct?
- Wolffian duct (mesonephric duct) is a paired organ found in humans during embryogenesis. They are male structures that include the epididymis, vas deferens and seminal vesical that differentiate from this structure
- Wolffian duct degenerates in females and develops in males
What are the Mullerian ducts?
• Mullerian ducts (or paramesonephric ducts) are paired ducts in the embryo that develop to form the cervix, the uterine tubes, the uterus and the upper one-third of the vagina. In the male they are lost.
Go through foetal sex determination
o Sex determining region on Y chromosome – SRY gene hence male dictates sex
o Presence of SRY gene causes Mullerian inhibitory factor (MIF) to be released by Sertoli cells in testes
o Mullerian ducts regress -> no uterus or fallopian tubes
o Dihydrotestosterone also produced – development of external male genitalia
o Female – no SRY gene -> no MIF -> Mullerian ducts form -> uterus and ovaries form
What happens at meiosis during reproduction?
o Interphase – cell contents replicate (2n ->4n)
o Meiosis 1 – mitosis, but crossing over and independent assortment occurs (4n -> 2n)
o Meiosis 2 – daughter cells divide to form haploid cells (2n -> n)
Go through oogensis
o Primordial germ cells = oogonia -> gametes = primary oocytes
o First meiotic division = puberty due to LH surge
o Primary oocytes -> secondary oocyte and polar body (most cytoplasm in secondary)
o Second meiotic division = post ovulation
o Secondary oocyte -> tertiary oocyte/ovum and polar body
What happens during spermatogenesis?
o Two daughter cells produced in mitosis:
Type A stay outside blood testes barrier and continue producing daughter cells
Type B -> primary spermatocytes that move through BTB
o Meiosis 1 = primary spermatocyte -> secondary spermatocyte
o Meiosis 2 = secondary spermatocyte -> spermatid
o Sertoli cells form BTB – tight junctions and basement membrane
What happens during spermiogenesis?
o Occurs in seminiferous tubules bordering Sertoli cells
o Spermatid -> spermatozoa
o Discards excess cytoplasm and grows flagellum
Go through the hypothalmic-pituitary-gonadal axis in males and females
o Male:
GnRH in hypothalamus -> FSH and LH in ant pituitary
FSH -> Sertoli cells -> inhibin release -> inhibits anterior pituitary
LH -> Leydig cells -> testosterone release -> inhibits hypothalamus and pit
o Female:
GnRH in hypothalamus -> FSH and LH in ant pituitary
FSH and LH -> oestrogen and progesterone release -> both have positive/negative feedback with hypothalamus and anterior pituitary
What is menopause and what are its symptoms?
o Cessation of menstruation – average age = 50 – degradation of follicles
o Decrease in oestrogen causes increase in FSH and LH – negative feedback
o Symptoms:
Vasomotor – flushes, sweats, palpitations
Psychological – irritability, lethargy, loss of libido
UG and skin – vaginal and skin dryness, brittle hair and nails
Osteoporosis – less bone tissue in bone, regulated by oestrogen
What is the blood testes barrier?
Research
