Reproductive and Endocrine Flashcards
What are the common clinical signs of hypothyroidism?
Weight gain with no change in appetite Poor exercise intolerance Thinning of coat- bilateral hair loss, flaky skin Decreased heart rate Mental dullness
Explain the following clinical signs of hypothyroidism: thinning of coat, decreased HR, mental dullness
Thinning of skin- thryoid hormone required for normal growth and development
Decreased HR- thyroid promotes responsiveness to sympathetic nervous system
Mental dullness- thyroid promotes axonal conductivity
What are the common clinical signs of hyperthyroid disease?
Increased appetite and weight loss
Hyperthermia
Excitable, irritable, aggressive, increased HR
Explain the clinical signs of hyperthyroidism?
Increased appetite/weight loss- increased metabolic rate
Excitable, irritable, aggressive- increased responsiveness to sympathetic nervous system
What blood tests are used to help diagnosis of hyper/hypoparathyroidism?
Testing for total and free T4
Endogenous canine TSH
Thyroglobulin autoantibodies
Hyperthyroidism- high serum T4 (total)
How can hyperthyroidism be treated?
Remove thyroid- surgery of radioactive iodine
Surgical thyroidectomy- upfront cost vs ongoing treatment- risk of damage to parathyroids
Radioactive iodine- destroys thyroid follicles, half life 8 days, serum T3/4 normalises after 1-2 weeks expensive
Effects of removing thyroid tissue- hypothyroidism, bilateral disease
Dietary restriction of iodine- only suitable for house cats
Thioureylenes- carbimazole metabolises into methimazole, inhibits synthesis of T3/4, orally administered
How can hypothyroidism be treated?
Thyroid hormone replacement
Oral administration absorbed from GI tract
Levothyroxine is T4
Liothyroxine is T3
How does the free amount of free hormone vary in treated animals with hypothyroidism?
Plasma protein binding of T3/4 varies
What are the adverse effects of treatment of hypothyroidism?
Hyperthyroidism, increased BMR, cardiovascular stimulant
What test results would you expect from an hypothyroid animal?
Endogenous TSH would be increased
T4 low- but not very sensitive
What do glucocorticoids do?
Promote gluconeogenesis in the liver, increases lipolysis, increases catabolism of proteins, inhibits growth, inhibits immune response
What is the common name for hyperadrenocorticism?
Cushings syndrome
What are the clinical signs of hyperadrenocorticism?
Hypergylcaemia (not above renal threshold) Tissue wasting Muscle weakness Pot belly Hair loss
What are the causes of Cushings disease (hyperadrenocorticism)?
Functional adrenal tumour (ACTH decreased, unaffected size shrinks)
What is hypoadrenocorticism and what are the clinical signs?
Hypoadrenocorticism- cannot produce enough cortisol and aldosterone
Clinical signs- hyperkalaemia (cardia arrhythmias), hypertraemia (circulatory collapse)
What blood tests are used for adrenal disorder diagnosis?
ACTH stimulation test- basal blood cortisol, take blood cortisol 30-60 mins after synthetic ACTH- in normal animals this stimulates basal cortisol
Dexamethozone suppression test- basal blood cortisol taken falling injection of synthetic glucocorticoid, normal animals clear suppression of basal cortisol
What is Addisons disease and how is it treated?
Hypoadrenocorticism- can be primary, secondary of latrogenic (sudden withdrawal of prolonged glucocorticoids)
Treated by replacement therapy- glucocorticoids and or mineralocorticoids
How can over-production of hormones of the adrenal cortex be treated?
Adrenal steroid inhibitors- trilostane
Dopamine receptor agonists- horses only
Mineralcorticoid receptor antagonists
What is the mode of action of trilostane, the route of administration and adverse effects?
MOA- synthetic steroid analogue, competitive inhibitor that inhibits corticosteroid synthesis
Lipid soluble- oral administration
Adverse effects- Hypoadrenocorticism, electrolyte abnormalities, inhibits progesterone synthesis
What is cushings diseased treated with?
Dopamine receptor agonists- pergolide
What are mineralocorticoid receptor agonists used to treat?
Not endocrine- used as diuretic- spironolactone
What is used for mineralocorticoid receptor agonists?
Aldosterone (native)- not available pharmacologically v short half life
Desoxycortone pivalate
What are glucocorticoid receptor agonists often used to treat?
Anti-inflammatories
What is the absorption, distribution and elimination of (pharmokinetcis) of glucocorticoids?
Absorption- absorbed by the GI tract, mucous membranes and skin
Distribution- transported bound to plasma proteins
Elimination- Duration of acting, short, intermediate and long (1/2 hour - 72 hours
What are the adverse effects of corticosteroids?
Toxic effects following long term high doses
Latrogenic hypo/hyperadrenocorticism
What are the clinical signs of parturient hypocalcaemia?
Skeletal muscle weakness, tremors, ataxic, recumbency, head tucked into flank, hypothermia, bloat, constipation, urine retention, dystocia, dilated pupils
Why is hypocalcaemia more common in older animals?
There is less bone remodelling so cannot react quickly to homeostatic mechanisms involving calcium
When does hypocalcaemia occur in sheep and bitches?
Sheep 3-4 weeks before parturition due to bone production
Bitches during peak lactation
How can kidneys disturb normal functioning parathyroid gland?
In chronic renal disease phosphate is retained leading to hyperphosphatemia which leads to hyperparathyroidism:
Hyperphosphataemia forms complex with ionised Ca2+ ions causing hypocalcaemia and release of PTH
Increased phosphorus reduces activation of vitamin D which activates calciferol which prevents inhibition of PTH
Why does hyperparathyroidism cause bone demineralisation?
PTH increases calcium mobilisation
This causes bone demineralisation
What blood tests can be used for disturbances of calcium metabolism?
Total serum calcium= Ionised calcium and protein bound calcium
Normally 50:50
PTH can also be measured
Primary hyperparathyroidism increases PTH, increased blood calcium
Primary hypoparathyroidism decreases PTH/blood calcium
What is the difference between primary and secondary hyperparathyroidism?
Primary- problem with parathyroid- functional tumour
Secondary- nutritional/renal
What drugs can be used that affect calcium metabolism?
Calcium replacement with calcium salts
Vitamin D preperations
What are the 4 calcium salts that are used?
Calcium Gluconate Calcium Carbonate Calcium Chloride Calcium Borogluconate IV or oral administration
What needs to be considered with oral administration of calcium?
Absorbed from the small intestine
Vit D3, PTH, acidic PH facilitate absorption
Dietary fibre, phytates, steatorrhea and araemia interfere with absorption
How can calcium balance be improved long term?
increased dietary calcium and administering with vitamin D3
What are the potential adverse effects of administering calcium?
Hypercalcaemia- particular detrimental with cardia/renal disease
Rapid IV- effects on the heart- Arrest and arrhythmias
How does vitamin D3 help phosphorus and calcium metabolism and what can they treat?
Range of hormones that alter metabolism
Latrogenic hypoPTHism following thyriodectomy and immune mediated hypoPTHism
Renal secondary hyperPTHism
How is Vit D3 administered and what are its adverse effects?
Oral administration- good GI absorption Protein bound but vit D binding globulin Excreted in feces Adverse effects- Narrow therapeutic index Hypercalcaemia Nephrocalcinosis Hyperphosphataemia
What is the difference between type 1 and 2 diabetes and which affects which species more?
Type 1- due to inadequate insulin secretion, more common in dogs
Type 2- due to abnormal target responsiveness more common in cats
What are common clinical signs of diabetic animals and explain them?
Weight loss- decreased protein synthesis/without glucose muscles breakdown for protein use for energy
Polydipsia and Polyuria- renal threshold is exceeded so glucose is not reabsorbed water follows, ECF decreases plasma osmolarity increases, hypothalamus stimulated thirst
Ketoacidosis- Liver uses B-oxidation to breakdown fatty acids excess acetyl CoA forms ketone bodies, large amount makes animal ill
CNS signs- levels of glucose in CSF directly proportional to blood sugar, high glucose in CSF draws water out of neurones causing dehydration and cell damage
What blood tests can be used for diagnosis of diabetes mellitus?
Hyperglycaemia
Glycosurai
Fructosamine- formed from glucose and serum proteins binding, reflects average of 1-3 weeks
Hyperlipiaemia- milk like blood plasma
How is insulin deficiency treated?
Insulin replacement
Insulin receptor agonists
Diet also needs to be managed
What are the adverse effects of exogenous insulin?
Hypoglycaemia- if severe treat with IV glucose infusion
Insulin resistance
What is the treatment of overdose of insulin?
Feed and give IV glucose
If doesn’t respond give glucagon
How do insulin formations vary?
According to species, concentration of zinc and size of Zinc crystals
What are antidiabetic agents other than insulin?
Sulphonureas- stimulates insulin release from B cells can induce hypoglycaemia
What is the aim of the diet to go along with treatment of diabetes?
Designes to maximise to the effect of exogenous insulin and minimise postprandial hyperglycaemia
Where do the ovaries of a bitch sit relative to kidneys?
Sit caudal to kidneys
Which ligament is in the free edge of the broad ligament and passes through the inguinal canal?
Round ligament
Which ligament of the bitch reproductives system is divided into mesovarium, mesosalpinx and mesometrium?
Broad ligament
What does the mesometrium, mesovarium and mesosalpinx of the broad ligament attach to and from?
Mesometrium- body wall to uterine horns
Mesosalpinx- body wall to uterine tubule
Mesovarium- body wall to ovary
Which two ligament of the bitch repro attach directly to ovary?
Suspensory and ovarian ligaments
What does the ovarian ligament contain?
Ovarian artery and vein
Which of the ovarian and suspensory ligaments are tight and loose?
Suspensory is tight
Ovarian loose
What does the ovarian ligament hold?
Holds the oviduct (continuation of the horn) close to ovary
What are the three types of uteri found in mammals and briefly describe them?
Simplex- one bid body no uterine horns
Bicornuate- poorly to moderately developed uterine horns (mare to cow)
Duplex- two car
Which animals have simplex, bicornuate and duplex uteri?
Simplex- primates
Bicornuate- mares, cows, bitch, queen, sow
Duplex- marsupials, some rabbits
Which of the following animals are not bicornuate and don’t have a single cervix: Cow, Mare, Sow, Bitch, Queen, Ewe?
None
All bicornuate and have single cervix
How does the topographical anatomy of the repro tract in cows and mares differ?
Mare dorsal ovaries
Cow ventral ovaries
In which species doe the corpus luteum not protrude from the ovaries?
Mares
Describe the structure and function of follicles?
Thin walled and fluid filled
Granulosa cells synthesis oestrogen
Dominant follicle produces lots of oestrogen and inhibin which inhibits FSH and surpasses further development of new follicles
Describe the appearance and structure of corpus lutea?
Filled with luteal cells
Sometimes central cavity
Grey yellow with yellow cut surface
Compare and contract cows and mares ovaries?
Cows- smaller, CL protrudes, ovulates from different places, extensive infundibulum
Mare- larger, kidney shaped, CL doesn’t protrude, distinct ovulatory fossa, small infundibulum
How can CL and follicles be identified on ultrasound?
Follicles are fluid filled spaces
CL are grannular
What makes up the oviduct and what are there functions?
Infundibulum- funnel shaped opening at ovarian end
Ampulla- large diameter, ciliated, site of fertilisatino
Isthmus- small diameter, thicker muscular wall, sperm stored
Why is the mare infundibulum able to be less extensive?
Most species ovulate at a random point so need extensive infundibulum to capture oocyte, mare always ovulated from a single ovulation fossa so doesn’t need extensive
What is the ovarian bursa?
Peritoneal sac encapsulating ovary in bitchez
What layers is the uterine tissue made up of?
Perimetrium
Myometrium
Endometrium- mucosa and submucosa
Which species have diffuse placentas and how are they structured?
Endometrial folds throughout the uterus contribute to maternal placenta
How does sheep and cows attach to amniotic sac?
They have distinct maternal caruncles
Describe the structure of the cervix
Thick walled and non-compliant
Cervical canal surrounded by folds or rings
In what animals does the cervix act as a barrier to sperm transport and how does the cervix isolate the conceptus during pregnancy?
Barrier to sperm transport in Ewe, Cow, Bitch, Queen
During pregnancy progesterone makes mucus viscous which ‘glues’ folds together
Describe the differing cervix structures of the Queen and bitch, Cow and ewe, Mare and Sow
Queen and Bitch- Small and smooth
Cow and Ewe- Distinct protrusions called cervical rings
Mare- no cervical rings but longitudinal folds are continuous with endometrial folds
Sow has interdigitating prominences
Why might a catheter be introduced through a cervix?
AI, Embryo transfer, Treating uterine infections
What is the name of the inner/outer sac in pregnancy?
Inner- Amnion
Outer- Chorioallantois- formed by fusion go inner allantois and outer chorion
What is the function of the placenta?
Provides an interface for metabolic exchange between dam and foetus
Transitional endocrine gland producing hormones to- maintain pregnancy
Stimulation of maternal mammary growth
Promotion of foetal growth
What are the functions of the amniotic membranes and fluid and the allantoic membranes and fluid?
Amniotic membranes and fluid- enclose foetus, hydrostatic protection, mucous at the end to form lubricant
Allantoic membranes and fluid- early collection of urine, hydrostatic protection
What is the allantochorion?
The foetal contribution to the placenta and will provide the surface for attachment to the endometrium of the dam
What is the name for the functional part of the foetal placenta?
Chorionic villus- small finger like protrusions that protrude towards the uterine endometrium- increase SA
How are placentas classified?
According to the distribution of the chorionic villi on their surfaces and their microscopic anatomy
What are the 3 categories of placenta and which species has which?
Diffuse- horses and pigs
Ruminats- Cotyledonary
Carnivores- Zonary
What is the difference between cow and sheep cotyledonary placenta?
Cows have convex caruncle attaching to chorionic tissue
Sheep hace concave caruncle attaching to chorionic tissue
Which species placentas are epitheliochorial and endotheliochorial?
Epitheliochorial- sheep, cow, pig, mare
Endotheliochorial- dogs and cats
Why do dogs and cats have a pigmented zone?
Maternal haemorrhage and necrosis- normal
How many umbilical blood vessels are there?
Two umbilical arteries
1 umbilical vein- bifurcates in ruminants
What is the function of the umbilical arteries, umbilical vein and urachus?
Arteries- left and right- internal iliac arteries to foetal maternal blood
Vein- foetal-maternal blood exhange
Urachus- bladder to allantoic cavity
What do the blood vessels/urachus eventually become?
Umbilical artery- round/lateral ligaments of the bladder
Umbilical vein- round ligament of the liver
Urachus- median ligament of bladder
What are the two basic models of penile anatomy?
Musculocavernous
Fibroelastic
What three parts does the penis consist of?
Base root- attaches to ischial arch
Shaft- main proportion
Glans penis- specialtes distil end
What is a musculocavernous penis dependent on for an erection?
Large corporal sinusoids that fill with blood
Which species have mucsulocavernous peni?
Dogs and horses
How is a dogs bulbs glandis unique?
Allows dogs to face in opposite directions
What changes occur in musculocavernous peni that allows an erection?
Elevates arterial blood inflow Dilation of corporal sinusoids Restricted venous outflow Elevated intrapenile pressure Penis increases in diameter
What muscles are associated with the pelvic urethra and penis and what are their functions?
Urethralis- striated, surrounds pelvic urethra moves semen into urethra
Bulbospongiosus- overlaps root of penis extends down caudal and ventral surfaces, covers bulbourethral glands
Ischiocavernosus- paired, short muscles in the root of the penis inset laterally above sigmoid flexure and connect penis to ischial arch
Retractor penis- smooth muscle- attach dorsally to coccygeal vertebrae and ventrally to ventrolateral sides of penis, Moves penis into sheath
Describe the mechanism of ejaculation?
Sensory intromission
Sensory stimulation of glans penis (temp and pressure_
Sudden powerful contractions of urethralis, bulbospongiosus and ishiocavernous
Expulsion of semen
What categorises a penis as fibro-elastic?
Limited erectile tissue cased in non-expandable dense tunica albuginea
Characterised by a sigmoid flexure
What is different about a fibro-elastic penis erection?
Erections is stiffening without a significant change in diameter
How is the sigmoid flexure maintained?
Maintained by a pair of retractor penis muscles which attach dorsally to coccygeal vertebrae and ventrally to the venters-lateral sides of the penis
What is different about a boars sigmoid flexure?
Pre-scrotal
Compare the glans penis in the boar, stallion, bull, ram and tom cat?
Boar- no glans, the free end terminates in spiral (locks into sows cervix
Stallion- urethral process is sunk into a deep fossa glandis
Bull- tapers to a point
Ram- similar to bull but has worm-like urethral process
Tom cat- cornfield spines to help stimulate reflex ovulation, disappear in neutered animals
What are calculi and what problem can they cause?
Calculi (stones) from the bladder can get caught in the penile urethra and the animal may be unable to pass urine and rupture the penis
Where are the common pinch points affected by calculi in the following species: Dogs, Bulls, Rams?
Dogs- base of the os penis
Bulls- proximal end of the sigmoid flexure/ischial arch
Rams- vermiform appendage
Describe the different appearance of scrotums in different species?
Bull and small ruminants- long, pendulous marked neck
Stallion- globular with poorly defined neck
Boar- subanal, lying close against caudal surface thighs
What are the three ligaments of the testis?
Proper ligament
Ligament of the tail of the epididymis
Scrotal ligament
Where is sperm stored in the testis?
Sperm stored in tail of epididymis
What is the function of the pampiniform plexus?
Countercurrent heat exchanger
What is the function of the accessory sex glands?
Produce seminal plasma- non cellular fluid portion of semen (packed lunch)
Small in immature animals/castrated before puberty
Post-pubertal castration leads to atrophy of glandular component
What are the 4 accessory sex glands?
Ampulla- enlargements of ductus deferens that open directly into pelvic urethra
Vesicular glands/seminal vesicles- paired glands dorso-cranial to pelvic urethra
Prostate- between junctions ofpelvic urethra and bladder
Bulbourethral glands- paired glands either side of pelvic urethra near ischial arch
