Semester Two - Regulation, Stress and Self Flashcards
What are the 9 major endocrine glands?
- Hypothalmus
- Pituitary gland
- Pineal gland
- Thyroid gland
- Thymus
- Parathyroid gland
- Adrenal gland
- Pancreas
- Gonads - testes (male), ovaries (female)
What is an endocrine gland? What does it do?
- Endocrine gland are ductless glands that release hormones directly in to the bloodstream.
- Produce, control and modify release of these specific hormones.
How is the endocrine system and nervous system closely related?
- They are both responsive to internal and external stimuli and together maintain homeostasis.
- Can regulate each others activity to bring about change in the body’s function.
What glands are regulated by the hypothalamic-pituitary-target gland axis feedback mechanism and how does it work?
- Thyroid gland
- Adrenal gland
- Gonads
- The hypothalamus secretes releasing hormones which are transported via the blood to the pituitary gland
- The releasing hormones induce the production and secretion of pituitary hormones that are transported by the blood to their target glands
- Feedback from the target glands to the hypothalamus and pituitary gland regulates hormone levels/functions in the body
How does homeostatic regulation of hormones through negative feedback work?
Hormones released by target gland are detected by the hypothalamus turning off the response.
Example to help with understanding:
- The hypothalamus secrete thyroid releasing hormone (TRH)
- This stimulates cells in the anterior pituitary to secrete thyroid-stimulating hormone (TSH)
- TSH binds to receptors on the thyroid gland, stimulating synthesis and secretion of thyroid hormones
- When blood concentrations of thyroid hormones increase above a certain threshold- TRH-secretions by the hypothalamus are inhibited and stop secreting TRH
How does homeostatic regulation of hormones through a direct negative feedback loop work?
The secretion of hormones is dependent on the levels in the blood and not the action of any releasing-hormones
Example to help with understanding:
- Blood glucose levels rise stimulating beta cells in the pancreas to release insulin
- Insulin facilitates entry of glucose into the cells of the body and blood glucose levels fall and the stimulus for insulin release disappears and insulin is no longer secreted
- Additionally Glucagon works in opposition to insulin – both act to regulate blood glucose levels
How does homeostatic regulation of hormones through positive feedback work?
A stimulus causes hormone production to increase
Example to help with understanding:
1. Lactation - hormone levels increase in response to the baby suckling which causes milk production to increase
2. Prolactin is secreted from the pituitary gland in response to nursing/suckling by the baby – increases milk production
3. Suckling by the baby also stimulates the hypothalamus which signals the posterior pituitary gland to produce oxytocin
4. Oxytocin stimulates contraction of the milk ducts
The increased pressure causes milk to flow through the duct system and be released through the nipple
What are other organs that have a endocrine function?
- GI (digestive)
- Renal
- Thymus
- Adipose tissue
- Placenta (during pregnancy)
What are the three common causes of endocrine pathophysiology?
- too much hormone (hypersecretion - graves disease: too much thyroxine)
- too little hormone (hyposecretion - type 1 diabetes: too little insulin)
- lack of response to target cell (type 2 diabetes: target cells insensitive to insulin)
What is the role of the thyroid?
- Produces t4 and t3 which control the rate at which glucose is used to supply the body with energy. (BMR)
- Regulates BMR - the minimum rate at which the body uses energy to stay alive.
- Produces calcitonin (reduces blood calcium level)
How do the nervous system and endocrine system differ?
Nervous system
- Performs short term crisis management
- Electro-chemical communicator– action potential /neurotransmitters
Endocrine system
- Acts slowly taking minutes, hours or days to produce regulating effects
- Chemical communicator – hormones
What hormones are released by the hypothalamus? (2) How does this relate to the posterior pituitary gland?
These hormones are released by hypothalamus and then travel to posterior pituitary gland where they are released.
- Antidiuretic hormone (ADH): main regulator of fluid in body
- Oxytocin: uterus contractions in labor
What hormones are released by anterior pituitary gland? (6)
- Thyroid stimulating hormone (TSH): travels to thyroid and stimulates T4 and T3.
- Growth hormone (GH): stimulates growth of long bones
- Prolactin (PRL): stimulates milk production
- Follicle stimulating hormone (FSH): stimulates production of ova and sperm
- Luteinizing hormone (LH): stimulates ovaries and testes
- Adrenocorticotropic hormone (ACTH): stimulates adrenal cortex to secrete glucocorticoids.
What hormone is released by the parathyroid gland?
Parathyroid hormone (PTH): main function raises calcium level in blood
What hormones are released by the adrenal medulla (inner)? (2)
- epinephrine
- norepinephrine
Major action is to raise BGL level, increase rate of metabolism, constrict certain blood vessels, fight or flight
What hormones are released by the adrenal cortex (outer)? (2)
- glucocorticoids (cortisol): increase BGL
- mineralocorticoids (aldosterone): promote reabsorption of Na+ and excretion of K+ in kidneys
What hormones are released by the pancreas? (2)
- insulin: reduces BGL
- glucagon: raises BGL
Regulation of glucose in blood and cells.
What hormones are released by the gonads? (3)
Testes:
- androgens (testosterone): support sperm formation, development and maintenance of male secondary sex characteristics
Ovaries:
- estrogens: stimulate uterine lining and growth, development and maintenance of female secondary sex characteristics.
- progesterone: promotes growth of uterine lining
How do hormones communicate with cells?
- Endocrine hormones are released then travel in the blood stream.
- Hormones are received by very specific receptor sites on cells.
- Similar to how a key fits a lock.
What other organs have an endocrine function? (5)
- intestines
- atria of heart
- ventricles of heart
- kidneys
- thymus
What are the main steps of the HPA axis?
The hypothalamic pituitary adrenal axis:
- Stimulated by an environmental stressor the hypothalamus secrete corticotrophin-releasing hormone (CRH) and ADH (arginine-vasopressin/AVP)
- CRH is transported to the anterior pituitary, stimulating the secretion of ACTH (corticotropin)
- Leads to activity in adrenal gland resulting in the release of stress hormones including cortisol, epinephrine, norepinephrine resulting is stress response in body.
- ADH (vasopressin) increases reabsorption of water by the kidneys, vasoconstriction and the contraction of blood vessels - increases blood pressure
What regulates the release of cortisol?
The HPA axis
What are some of the functions of cortisol?
- Regulates protein metabolism
- Increases BGL by stimulating gluconeogenesis
- Prevents cells from losing sodium and accelerates the rate of potassium excretion - regulate the action of cellular sodium-potassium pump
- Helps regulate pH
- Reduces immune response - cortisol blocks T-cells from proliferating and preventing interleukin signals
- Reduces immune response - by inhibition of histamine secretion
- Excess cortisol can cause atrophy of hippocampus - damage to memory (often reversible)
- Chronic levels of high stress disrupt the feedback mechanism resulting in the failure of feedback inhibition to operate and the continued release of cortisol
What is the difference between physiologic and pharmacologic therapy?
- The goal of Physiologic Therapy is to replace the natural adrenal steroid for example Addison’s disease
- The goal of Pharmacologic Therapy is to relieve the symptoms of non hormonal conditions and diseases for example COPD, asthma, Rheumatoid Arthritis, Ulcerative Colitis
What are some common side effects of steroid medication? (there’s lots, just name a couple)
- Dangerous to suddenly stop the medication as steroids override the body’s usual adrenal function
- Fluid retention (oedema) and sodium retention
- Thin skin and hair growth
- Bruising
- High or increased blood pressure
- Susceptibility to infections
- Weight gain and fat deposits face, between shoulders
- Osteoporosis and osteopenia
- Pathological bone fractures- particularly in the spine and ribs
- Insomnia, mood changes (occasionally acute psychosis)
- Alterations in blood glucose levels and potassium
- Loss of muscle mass
- Secondary sex characteristics of the other sex
- Heart failure
- GI ulceration
- Poor growth in children and adolescents (hip bone deformity)
What is the best route of administration for steroid medication?
Local administration of steroids is always preferred over systemic routes for example:
- Inhaled glucocorticosteroids for asthma and COPD
- Applied topically for skin conditions
- Injected directly into the joint for inflammatory joint conditions for example frozen shoulder
What causes adrenal insufficiency?
- Adrenal crisis may occur due to adrenal insufficiency
- Adrenal insufficiency can be primary or secondary
Addison’s disease -primary adrenal insufficiency:
- the adrenal glands do not produce enough cortisol and aldosterone
- 80% - autoimmune - primary adrenal insufficiency occurs when at least 90 percent of the adrenal cortex has been destroyed
Secondary insufficiency:
- Stoppage of Corticosteroid Medication
- Surgical Removal of Pituitary Tumors - ACTH-producing tumors of the pituitary gland that cause Cushing’s syndrome
- Tumors (most commonly adenoma), infection in the pituitary
- loss of blood flow to the pituitary (eg. post partum hemorrhage)
What are some signs and symptoms of adrenal crisis?
Dizziness or light-headedness Flank pain Headache High fever Joint pain Low blood sugar Low blood pressure Dehydration Confusion Loss of consciousness Coma Rapid heart rate Rapid respiratory rate (tachypnea)
What is the role of insulin in BGL regulation?
- Glucose is stored as glycogen in the liver (reserve approx. 6 hours) and peripherally in skeletal muscle (in much smaller quantities)
- Insulin allows glucose to move from the blood the cell
- Insulin is released from the beta cells in the pancreas
- Insulin stimulates protein synthesis and free fatty acid storage in adipose tissue (anabolic steroid) and facilitates the movement of serum glucose into the cells.
The stimulus for insulin secretions is a HIGH blood glucose level. True or false?
True.
The stimulus for glucagon is a HIGH blood glucose level. True or false?
False. The stimulus for glucagon secretion is a LOW blood glucose level
- Glucagon is secreted by the alpha cells of the pancreatic islets in opposition to insulin
- The effect of glucagon causes the liver to release the glucose it has which increases blood glucose
- Glucagon causes the liver and muscles to produce glucose by utilizing protein and fat
What is GFR?
The glomerular filtration rate.
Glomerular filtration rate (GFR) is the volume of fluid filtered from the renal (kidney) glomerular capillaries into the Bowman’s capsule per unit time.
What is creatinine?
Creatinine - waste product from muscles, a more accurate marker of kidney function than urea.
What is the most accurate measure of renal function?
Estimated glomerular filtration rate (eGFR) - the eGFR is the most accurate measure of renal function.
Serum creatinine is used to estimate the eGFR using age, sex and race
eGFR calculated by computer and reported with the creatinine blood test
Electrolytes - sodium, potassium, chloride and bicarbonate usually measured.
What can cause a UTI?
- E. coli
- Sexual activity
- Contraception – spermicide, diaphragm, condom
- Catheterisation
- People at high risk: women 50x greater than men – short urethra, spinal cord injury, people who have problems emptying bladder, enlarged prostate or kidney stones, diabetes, pregnancy, long term catheter (almost 90-100% more likely). Short term catheter (10-30%)
What investigations are used to identify a UTI?
- Urinalysis test
- Urine culture
Signs and symptoms of UTI?
- Urgency of urination
- Frequency
- Pain when urinating
- Pressure in bladder
What is treatment for UTI?
Antibiotics - trimethoprim is first choice
How can a UTI be prevented?
- 6-8 glasses of water daily
- urinate regularly when urge arises
- urinate shortly after sex
- woman should wipe from front to back
- cotton underwear
- loose fitting clothes
What is pyelonephritis? What causes it?
- Follows on from a UTI
- Pyelonephritis is bacteria that invades the renal cortex and medulla
Causes: - Untreated UTI
Signs and symptoms of pyelonephritis:
- Intense pain
- High fever
- Loin pain
- GI upset
- Blood cells and pus in urine
What are the 8 types of incontinence?
- Stress incontinence: associated with coughing sneezing, physical activity
- Urgency incontinence: detrusor muscle over activity
- Overactive bladder syndrome: more than 8x per day
- Mixed incontinence: combination of stress and urgency incontinence
- Overflow incontinence: obstruction at bladder neck or impairment of detrusor contractility, leakage. Can be caused by stroke ect.
- Functional incontence: cognitive and physical impairment that stop you voiding independently.
- Post void dribbling: little bit of leakage after void
- Urogenital fistula: bladder/urethra/vagina rip. Due to complication from gynae surgery such as hysterectomy
What are some causes of incontinence?
- Previous vaginal delivery
- Obesity
- Prostate surgery
- Damage to CNS or nerve damage or external urethral sphincter
- Infants
- Elderly
- 6x more common in females than males
- Detrusor muscle problems
What can assist with the management of incontinence?
- Bladder training
- Pelvic floor exercises
- Anticholinergics – oxybutynin (Ditropan), tolterodine (Detrol), darifenacin (enablex)
- Triicyclic antidepressants – imipramine (tofranil) used to treat mixed urge/stress incontinence, duloxetine (cymbalta) used to treat stress incontinence
- Pessary – ring inserted in vagina
- Botox injection in to bladder muscle
- Surgery or catheterisation
Benign Prostatic Hyperplasia (hypertrophy BPH), what is it?
Enlarged prostate, non-cancerous
What is the cause of Benign Prostatic Hyperplasia?
- High levels of di-hydro testosterone (DHT) which stimulate growth of prostate
- DHT synthesised by testosterone in the prostate gland
- Testosterone levels decrease with age as oestrogen levels increase. Oestrogen stimulates prostate growth.
What are some signs and symptoms of Benign Prostatic Hyperplasia (hypertrophy BPH)?
- Difficulty to start to void
- Poor flow of urine
- Need to strain to pass urine
- Frequency
- Stopping and starting/stuttering
- Nocturia
What is an Acute Kidney Injury? (AKI)
- The same thing as acute renal failure.
- Defined as rapid or abrupt decline in renal filtration function
- AKI often associated with acute illness, upper or lower resp tract infection. UTIs, Sepsis
- It is a medical emergency, you must identify and treat the cause
What are the three main causes of Acute Kidney Injury?
- Prerenal (blood flow to kidney): interference with renal perfusion eg. Hypervolemia, GI bleeding, trauma, vomiting and diarrhoea, cardiogenic shock, MI, fluid volume shift, medication NSAIDS, ACE inhibiters and ARBs.
- Intra/intrinsic renal causes (inside kidney): characterised by direct damage to nephrons, may be secondary to another illness, acute tubular necrosis (death of epithelial cells), acute glomerulonephritis (acute inflammation of kidney), crush injury, severe transfusion reaction, infections
- Post renal causes (urine from kidney): interference with outflow of urine from kidney. Can be caused by blockage of flow of urine resulting in back pressure to kidney causing damage to nephrons. Obstruction in urinary tract. Renal calculi (kidney stones). Prostatic enlargement. Pelvic malignancy.
What are signs and symptoms of Acute Kidney Injury?
- Decrease fluid output
- Swelling/oedema
- Drowsiness
- SOB
- Fatigue
- Confusion
- Nausea
What is Chronic Renal Disease? (CKD)
- Term for chronic renal failure due to long term disease or damage to kidneys
- Most people that with present with acute renal injury have some degree of chronic renal damage.
- Higher prevalence in Maori and pacific due to high incidence of diabetes and hypertension
- 5 stages (1 is mild, 5 is severe)
What are some causes/risk factors of Chronic Renal Disease? (CKD)
- Diabetes
- Hypertension
- Cardio vascular disease
- Other renal disease or abnormality including persistent protein or blood in urine
- Family history of CKD or other renal disease
- Long term use of medication – diuretics and lithium, ACE inhibitors, NSAIDs
- CKD is an independent cardio vascular risk factor
- More people with CKD die of cardio vascular disease than end stage renal disease
- History of any risk factors mentioned above
What is End Stage Renal Disease? (ESRD)
CKD stage 5, caused by poor management of CKD
What are signs and symptoms and the very end of ESRD?
- At very final stage – hiccups, uremic frost, coma, convulsions. Assess for renal replacement therapy: dialysis or renal replacement – some people are not suited to dialysis and some choose not to. Without dialysis – survival is generally 6 to 8 months.
What is haemodyalisis?
- Surgical formation of an AV fistula connecting an artery to a vein
- Three sessions a week that last four hours a week
- Two cannula are inserted in to AV fistula which remove blood and transfer to dialysis machine
- Dialysis machine is a series of membranes that act as filters and dialysate membranes filter waste which are passed in to dialysate fluid and then that fluid is pumped out of the dialyser and blood is passed back through a second needle
- During haemodialysis, they have a very strict fluid intake because 2-3 days of fluid is removed in four hours
What is peritoneal dialysis and what are the two types?
- Surgical incision in abdomen, just below navel, tenckhoff catheter is inserted in to incision. Dialysate fluid passes through the catheter in to the peritoneal cavity. After dialysis, the end of the catheter is sealed.
- Two types
1) continuous ambulatory peritoneal dialysis (CAPD) – this involves exchanging old dialysate fluid that contains waste products and excess fluid with new dialysate. Exchange of old dialysate in to a waste bag, new in to peritoneal cavity. Takes 30-40 minutes to complete. Requires 3-4 exchanges a day. As the blood passes through the peritoneum, the dialysate fluid draws out waste products and excess fluid from the blood in to the fluid.
2) automated peritoneal dialysis (APD) – same principals to control drainage of fluid, exchange is over night, takes 8-10 hours, final exchange of the dialysate is in place throughout the day.
What is Addison’s disease?
- Opposite of Cushing’s
- Disorder of body producing insufficient hormones of adrenal glands. Not enough adrenal hormones (cortisol, aldosterone).
What is Cushing’s syndrome and Cushing’s Disease?
- Syndrome is excessive levels of cortisol in blood - common cause by taking medication already high in cortisol – too much cortisol (steroid medication, inhalers, topical)
- Disease caused by tumour in pituitary gland in which pituitary releases the hormone ACTH.
What is diabetes type 1?
- Autoimmune condition
- Insulin dependent *
- Body attacks beta cells so body cannot produce insulin
- absolute insulin deficiency
What is diabetes type 2?
- Insulin resistance, issue at receptor sites on cell membrane
- a deficiency of insulin, the body is unable to produce adequate insulin to meet the needs.
What is the role of insulin in normal function?
Normally, a rise in BGL after a meal triggers pancreatic beta cells to release insulin. Insulin works as a key and stimulates cells to take the glucose from the blood.
What does the HbA1c test?
It measures glycated haemoglobin - this is haemoglobin that has joined with glucose in the blood. It gives an overall picture of average BGL over a period of 4-6 weeks.
What is metabolic syndrome?
- Group of features that are linked to the body’s metabolism
- Fat distribution associated with altered metabolic profile
- Causes of syndrome is associated with cortisol – chronic
- Define syndrome of co-occurrence of three risk factors: high BP, dyslipidaemia and central obesity. Obesity –> insulin resistance –> metabolic syndrome
What is Diabetic Ketone Acidosis? (DKA)
- Body burns fat because there is no glucose for energy
- Acute
- If you have high BGL, you take insulin to lower BGL, insulin releases glucose
- Normally, glucose is used for energy from liver, in diabetics, body burns fats to use for energy.
- Caused by a diabetic not taking insulin or eating.
- Common prior to diagnosis – glucose not being released, don’t know what’s going on – not taking insulin.
- Can be caused by infection or trauma.
- Fatigue, weight loss, thirst, smelly, unconsciousness, coma, death
- High BGL.
- Treated with insulin
- Acid base balance affected
What is the mode of action of metformin?
- Reduction of gluconeogenosis
- Stops liver releasing stored glucose
- Increases insulin sensitivity improving glucose uptake in peripheral muscle and adipose tissue
What is the difference between an anion and a cation?
Positively charged ions = cations +
Negatively charged ions = anions -
Are bicarbonate, phosphorus and chloride anions or cations?
Anions
Are sodium, potassium, magnesium and calcium anions or cations?
Cations
Which electrolytes are intracellular?
Potassium, phosphorus, magnesium
Which electrolytes are extracellular?
Sodium, chloride, bicarbonate
Which electrolyte is equal in ICF and ECF?
Calcium
