Endocrine 2 Flashcards
Describe the Adrenal Glands
found superior to each kidney in the retroperitoneal space, composed of adrenal cortex - produces steroid hormones that affect homeostasis, adrenal medulla - norepinephrine, epinephrine dopamine - these cause ‘fight or flight’ response to physical or emotional stress
Describe the roles of norepinephrine and epinephrine
increases heart rate - increases cardiac output and b.p.
increase blood flow - to heart, liver, skeletal muscles and adipose tissue
dilate airways - and increase blood glucose levels
Describe the Thymus Gland
found behind the sternum, secretes thymosin - important in immunity
Describe the Pineal Gland
found in the brain, thought to contribute to setting the body’s biological clock - retina perceives less light stimulating the pineal gland to secrete melatonin - which promotes sleepiness
Describe the gonads - the ovaries
produce oestrogen and progesterone and are responsible for secondary sex characteristics - enlargement of breasts and widening of hips at puberty, ovaries produce inhibin - reduces secretion of FSH, during pregnancy = relaxin secreted - helps maintain suitable uterine environment
Describe the gonads - the testes
they secrete testosterone - enables the descent of the testes before birth, they regulate sperm production, stimulates secondary sex characteristics - such as beard growth and deepening of the voice
Dysfunction of the Endocrine System can be widespread and can be caused by …
Hyposecretion or Hypersecretion of hormone
Faulty/inaequate numbers of hormone receptors
DISORDER - POSTERIOR PITUITARY GLAND diabetes insipidus (DI)
defects in ADH receptors/inability to secrete ADH
CAUSES - traumatic damage to posterior pituitary/hypothalamus, non-functional receptors, kidney damage
EFFECTS - excretion of large volumes of urine with resulting dehydration and thirst, death may occur in sufferer of DI if without water for a day or so
DISORDER - PANCREATIC ISLET DISORDERS diabetes mellitus
Type 1 diabetes = insulin level low because person’s immune system destroys the pancreatic beta cells,
Type 2 diabetes = non-insulin dependent diabetes mellitus (NIDDM) more common, 90% of all cases
CAUSES - insulin is unavailable to aid transport of glucose into body cells = blood glucose level is high and glucose ‘spills’ into urine (glycosuria)
EFFECTS - excessive urine production due to an inability of the kidneys to reabsorb water, excessive thirst and excessive eating
DISORDER - THYROID GLAND congenital hypothyroidism
hypo secretion of thyroid hormones (present at birth) can cause severe mental retardation and stunted bone growth
hypothyroidism during the adult years produces myxedema sluggishness/weight gain
CONDITION - Hyperthyroidism is Grave’s Disease
REASON - thyroid gland continually over production of thyroid hormones
EFFECTS - an enlarged thyroid and oedema behind the eyes, - called exophthalmos which causes the eyes to protrude
DISORDER - PARATHYROID GLAND hypoparathyroidism
too little parathyroid hormone = deficiency of Ca2
CAUSE - accidental damage to parathyroid glands or to their blood supply during thyroidectomy surgery
EFFECTS - abdominal cramps, brittle nails, dry hair and skin
DISORDER - PARATHYROID GLAND hyperparathyroidism
overproduction of parathyroid hormone = blood levels of Ca2 raised
CAUSE - tumour of one of the parathyroid glands
EFFECTS - soft and easily fractured bones, formation of kidney stones, personality changes and lethargy
DISORDER - ADRENAL GLAND cushing’s syndrome
hyper secretion of cortisol by the adrenal cortex
CAUSES - adrenal gland tumour or a tumour elsewhere that secrets ACTH - stimulates excessive secretion of cortisol
EFFECTS - redistribution of body fat, resulting in a rounded, flushed ‘moon face’
DISORDER - ADRENAL GLAND addison’s disease
hypo secretion of glucocorticoids and aldosterone
CAUSES - problems with adrenal gland which affects secretion of glucocorticoids and aldosterone
EFFECTS - abdominal pain/weakness can progress to very low blood pressure and coma
DISORDER - PITUITARY GLAND giantism
hyper secretion of HGH during childhood causes an abnormal increase in the length of long bones
DISORDER - PITUITARY GLAND pituitary dwarfism
hypo secretion of HGH in childhood slows bone growth and the epiphyseal plates close before normal height is reached
DISORDER - PITUITARY GLAND acromegaly
hyper secretion of HGH adulthood - epiphyseal plates are already closed, the bones of the hands, feet, cheeks and jaws thicken and the nose enlarges.
