CBL 2 W3-4 GI and Endocrine Flashcards
What is schistosomiasis ?
Schistosomiasis is an acute and chronic parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma.
What type of tick causes Lyme disease
Ixodes Ricinus in the UL
What is zika virus?
Virus transmitted via mosquitos in Africa, South Asia, Carribean etc.
What is the most common mosquito to transfer malaria?
P.Falciparum
What is the first line treatment for severe Malaria?
IV Artemisinin
Where are travellers usually to catch Dengue?
Southeast Asia
Treatment for dengue
supportive (no admission, Paracetemol)
What antibodies are produced in response to dengue?
Memory IgG antibodies
Type of mosquito for dengue
aedes species
Dengue shock, capillary leak syndrome treatment
aggressive IV fluid management (note NOT anti virals)
Is dengue serious?
First time, no, second time more serious!
What is Dengue shock?
Severe dengue occurs as a result of secondary infection with a different virus serotype. Increased vascular permeability, together with myocardial dysfunction and dehydration, contribute to the development of shock, with resultant multiorgan failure.
Effects of dengue on the liver?
Severe Dengue can cause fatty liver and acute liver failure.
Dengue symptoms
Most asymptomatic but:
High fever
Headache
Body aches
Nausea
Rash.
Note:Most will also get better in 1–2 weeks.
Malaria symptoms
Fever and Flu-like illness, including shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Malaria may cause anemia and jaundice (yellow coloring of the skin and eyes) because of the loss of red blood cells.
What are neglected tropical diseases?
associated with poverty (lack of resources etc) but are mostly preventable and treatment
What is rabies?
(mention where and who affected, and how is it acquired?)
Asia, Africa,
40 percent under 15
From dogs (that are not vaccinated)
What is Leishmaniasis?
What is Lymphatic Filariasis
What is Trachoma?
What are the symptoms of Rabies?
headache, fatigue, hallucinations, tingling of wound, Insomnia, aggression, hydropobia, excessive salavation, throat spasms
What is management of Rabies?
HRIG vaccine
Direct immunoglobulin into wound injected
What is prognosis of Rabies?
What is the incubation time of rabies?
In terms of their relation to connective tissue, compare endocrine and exocrine glands.
Exocrine maintains relationship to surface via duct system while endocrine is seperated with its own connective tissue capsule.
Where is the pituitary gland located?
In the Sella Turcica of the Sphenoid bone and enclosed by a connective tissue capsule.
Note: Close proximity to the oral cavity
What is the infundibulum?
It connects the hypothalamus with the pituitary gland, comprising of both blood vessels and nerves.
What are the two parts of the pituitary gland and what are there general functions?
Anterior = Hormonal
Pituitary = Nervous
What are the cells present in the anterior pituitary gland and what do they produce?
-Somatotrophs = GH
-Mammotrophs = Prolactin (act on the breast)
-Corticotrophs = ACTH (adrenocorticotropic hormone) (acts on the kidney)
-Throtrophs - TSH (act on thyroid)
-Gonadotrophs FSH and LH (reproductive hormones)
What cell type is the majority cell type in the Anterior Pituitary?
Somatotrophs
What is the Hypophyseal portal system?
Blood vessels connecting the hypothalamus to the anterior pituitary.
What is the posterior pituitary composed of?
Unmeylinated axons of the neurosecretory cell bodies that originate in the SUPRAOPTIC AND PARAVENTRICULAR NUCLEI OF THE HYPOTHALAMUS.
What 2 structures would you expect to see on a histilogical slide of a posterior pituitary?
1.Herring Bodies = Dilations of axons to store hormones
2.Pituicytes = Support cells
What does the Supraoptic nucleus of the hypothalamus store?
ADH
What does the Paraventricular Nucleus of the hypothalamus store?
Oxytocin
What are the main 2 cell types of the thyroid?
1.Follicular cells
2.Parafollicular / C cells
What do the Follicular cells produce and why?
T3 and T4 to regulate metabolic rate as well as body growth and development
What do the Parafollicular / C cells produce?
Calcitonin
What are the effects of Calcitonin?
1.Decreases blood calcium
2.By decreasing bone reabsorption by the osteoclastes
3.Increase bone formation by osteoblasts
Where are the Parathryroid lobes located?
Sit posteriorly on either side of the thyroid.
Where is the thyroid located and describe its appearance?
1.(Anterior + Lateral surface) of Upper trachea
2.Bilobed
What is Goitre?
Swelling of the neck (i.e thyroid)
Describe the production of T3 and T4 in the thyroid.
- Follicular cells produce THYROGLOBULIN
2.This is stored in the centre of the follicle as COLLOID
3.Thyrotrophs of the Ant.Pit release TSH
4.This stimulates the reabsorption of Thyroglobulin
5.And then it is broken down my lysosomal action to T3 and T4
6.Released into bloodstream :)
What is the purpose of Thyroglobulin?
Storage form of T3 and T4.
What is the effect of Hyperthyroidism on Colloid levels?
Decreases
What is the effect of Hypothyroidism on Colloid levels?
Increases
Where is the adrenal gland located?
Suprarenal = above the kidney
What are the 2 parts of the adrenal glands?
1.Cortex
2.Medulla
What hormones and produced in the Cortex of the Adrenal gland?
-Mineralocorticoids
-Glucocorticoids
-Androgens
What hormones does the Medulla of the Adrenal glands produce?
Catecholamines
-Adrenaline
-Noradrenaline
What are the 3 zones of the adrenal cortex?
1.Zona Glomerulosa
2.Zona Fasciculata
3.Zona Reticularis
What happens in the Zona Glomerulosa ?
Production of Mineralcorticoids e.g Aldosterone
What happens in the Zona Fasciculata?
Influenced and controlled by ACTH that is released from the anterior pituitary gland, this is where GLUCOCORTICOIDS (e.g Corticoids) are produced
What happens in the Zona Reticularis?
Production of androgens (sex hormones)
What hormones are secreted from the Enteroendocrine cells?
GASTRIN = stimulates gastric acid secretion
CHOLECYSTOKININ (CCK) =stimulates gall bladder contraction
MOTILIN = stimulates gastric and intestinal motility
SECRETIIN = stimulates pancreatic enzyme secretion and inhibits gastric acid secretion
What does secretin inhibit?
Gastric acid secretion
Where are the Enteroendocrine cells located?
Diffusely arranged in the GI epithelium
What does Oxytocin do?
Stimulates Uterine Contraction and Milk Ejection
What does ADH do?
-Increases H2O permeability and absorption in renal collecting ducts
-Vasocntricts to increase BP
What are the 7 tropic hormones?
1.GH
2.TSH
3.ACTH
4.PRL (prolactin)
5.FSH
6.LH
What are Hypothalamic Hypophysiotropic hormones?
Hormones that are released by the hypothalamus and act on the Ant.Pit.
List the Hypothalamic Hypophysiotropic.
1.Growth Hormone Releasing Hormone
2.Growth hormone inhibiting hormone (Somatostatin)
3.Thyroid Releasing Hormone
4.Corticotrophin releasing hormone
5.Prolactin releasing hormone
6..Prolactin inhibiting hormone (Dopamine)
7.Gonadotrophin releasing hormone
List the categories of causes for Primary Hyposecretion.
Genetic, Dietary (lack of iodine), Chemical / Toxic, Autoimmune diseases or Latrogenic (surgical removal)
What is Primary Hyposecretion?
Too little hormone is secreted due to abnormality within gland
What is Secondary Hyposecretion?
Gland is normal but too little hormone is secreted due to deficiency of its Tropic Hormones.
What is Tertiary Hyposecretion?
Gland is normal but too little hormone is secreted due to deficiency of Hypothalamic Releasing Hormone.
Of all of the pituitary hormones, which one when deficient would be a threat to life?
Cortisol
What are the causes of Hypersecretion?
Tumours
What is primary hypersecretion?
Abnormality is WITHIN the gland
What is secondary hypersecretion?
Excessive stimulation from OUTSIDE the gland
What are the consequences of high ACTH?
Cushing’s Disease
What are the consequences of high Prolactin?
Impaired reproductive function
What are the consequences of high ADH?
Fluid retention and Low plasma osmorality
What are the consequences of high hGH in children?
Gigantism
What are the consequences of high hGH in adults?
Acromegaly
Describe the pathway of synthesis and secretion of Thyroid hormone.
- Iodine Trapping
=Iodine /Na+ Co transporter transports Iodine into follicular cells
2.Endosome containing colloid with the hormones inside fuse with lysosomes to cleave the T3 and T4 where it then leaves the follicle
How is Radioactive Iodine used diagnostically and what does it indicate?
-Used to investigate Thyroid hormone production in thyroid.
-Thyroid mops up Iodine (takes it up), so the AMOUNT OF IODINE ABSORBED BY THE THYROID IS IN DIRECT CORRELATION TO THE HEALTH OF THE THYROID
How are thyroid hormones transported in the plasma?
As they are Lipophillic they need to bind binding proteins :
-Thyroid Binding Globulin
-Thyroid Pre-Binding Albumin
-Thyroid Binding Albumin
How does Thyroid hormones increase basal metabolic activity?
By increasing the no. of Na+/K+ ATPase pumps
What are the actions of T3 and T4?
Increase metabolism:
-Increase BMR (Basal metabolic rate)
-Calorigenic effect (increased production of heat as a bi product of metabolism)
-Carbohydrate metabolism (increased absorption of glucose, glycogenolysis, and gluconeogensis.
-Lipid Metabolism (Lipolysis to increase circulating Free Fatty Acids and FFA oxidation, decreases cholesterol)
-Protein metabolism (increased protein synthesis and protein breakdown)
What is primary hypothyroidism?
Problem within the Thyroid gland which causes failure of thyroid gland to respond to TSH
Name 4 causes of Primary Hypothyroidism.
1.Thyroiditis e.g Hashimoto’s disease
2.Severe iodine deficiency
3.Severe deficiency of one or more synthesis enzymes
4.Removal or dysfunction of thyroid gland
Name 2 examples of Thyroiditis.
1.Hashimoto’s
2. Chronic Lymphocytic thyroiditis
What is Secondary Hypothyroidism?
Deficient TSH production
What is Tertiary Hypothyroidism?
Deficient TSH secretion due to deficient TRH secretion
What are the 3 causes of Hyperthyroidism from most common to most rare.
1.Autoimmune (e.g Grave’s)
2.Thyroid Adenoma
3.TSH-secreting adenoma
What causes goitre in Grave’s disease?
The inflammation of the thyroid glands on the neck due to antibodies that mimic TSH and stimulate the thyroid
What would you expect your T4, TSH and TRH to be in Primary Hypothyroidism?
T4 decreases
TSH increases
TRH increases
What would you expect your T4, TSH and TRH to be in Secondary Hypothyroidism/ Pituitary Hypothyroidism?
T4 decreases
TSH decreases
TRH increases
What would you expect your T4, TSH and TRH to be in Hypothalamic Hypothyroidism (Tertiary)?
T4 decreases
TSH decreases
TRH decreases
What would you expect your T4, TSH and TRH to be in Graves’ disease?
T4 increases
TSH decreases
TRH decreases
What is Exophthalmos?
The out bulging of the eyes you see in Grave’ disease
How does Emotional stress or Chemical stress affect Cortisol secretion?
- E.g Anxiety and Hypoglycaemia
- Hypothalamus release Corticotropic releasing hormone
3.Acts on the Post. Pit portal system and acts on the Corticotroph cells within the Ant.Pit
4.Zona Fasciculata RELEASES CORTISOL
5.ACTH and Corticotrophin Releasing Hormone are now downregulated
Describe the Diurnal rhythmic release of ACTH.
ACTH release follows a wake sleep cycle (diurnal rhythm)
-low in late night 11pm-3am
-Peak at 7-9am when you wake up
= this pattern is reversed in people with night shifts
As there are cues from light that affects the ACTH release
What hormone does ACTH control (i.e initiate release of)?
Cortisol
How would you take a cortisol measurement to check for deficiency?
Take a blood sample at 8-9am when it is supposed to be high when you suspect deficient cortisol levels.
Note: Due to pulsatile release of cortisol random measurement timings would be useless
How does cortisol travel in the blood?
Bound to Transcortin (85 % are bound in the blood)
If a patient has Cushings what would be used to diagnose?
-Urinary free cortisol would be high
-Cortisol levels would have to be monitored over a 24hr period
How do glucocorticoids affect muscle?
Catabolic affect = breaks amino acids down favouring a negative nitrogen balance and therefore a loss of muscle
How do glucocorticoids affect Liver?
Anabolic = Gluconeogenesis and Glycogenesis
How do glucocorticoids affect fat cells?
Lipolysis (Free fatty acid mobilisation)
How do glucocorticoids affect Immune system and inflammation?
Supresses it
Note: Good clinical intervention to treat the symptom of inflammation of an autoimmune disease
What are the signs of Cushings Disease?
-Fat deposition in belly and face
-Easily bruised
-‘Moon face’ = fat depositions and redness
-Dorsocervical fat depositions - i.e on the back between the shoulder pads
-Striae
-Osteoporosis (inc pathological fractures)
-Suppression of immune system
-Delayed healing of fracture and soft tissue injuries
Name the 3 actions of aldosterone.
-Increased Na+/H2O absorption
-Increased K+/H+ secretion
-Increased Blood Volume / BP
What 3 things does Aldosterone deficiency lead to?
- Increased loss of Na+ and H2O in the urine
= Dehydration, Plamsa depletion and Hypotension
2.Renal retnetion of K+
=Hyperkalaemia and cardiac excitability which can cause ventricular fibrillation
3.Renal retention of H+
=Metabolic acidosis
What is Conn’s Syndrome
A rare case of primary hyperaldosteronism with 75% of cases due to Adrenal adenoma carcinoma
What is secondary hyperaldosteronism?
Rare overactivity of the RAAS due to renin secreting tumour which can affect the heart
If one of the adrenal glands is destroyed, how does the body compensate?
Hypertrophy of the other adrenal gland
What is Addison’s Disease?
Destruction of BOTH adrenal cortices causing a lack of glucocorticoids, mineralocorticoids and adrenal androgens.
What are the effects of lack of glucocorticoids?
-Hypoglycaemia
-Reduction in fat and protein metabolism
-Weight loss
-Poor exercise tolerance
-Poor stress tolerance –> Death
What are the effects if lack of mineralcorticoids?
-Decrease in Na+
-Increase in K+
Increase in H+
-Hypovolaemia 9decreased blood volume)
-Decrease in cardiac output –>Circulatory collapse –> Shock –> Death
Describe the differing effects of a lack of adrenal androgens between men and women.
Not a major effect especially with men since they produce testosterone. More damaging in women due to their libido, can cause depression but not fatal.
What is the treatment for Addision’s disease?
Hormone replacement