The Endocrine System (part 3) Flashcards
state 2 functional facts about the Posterior Pituitary Gland
- does not synthesise hormones, only secretes them
2. secretes neuropeptides synthesised in the hypothalamus
state 2 hormones the Posterior Pituitary Gland secretes, and their functions
- Oxytocin - involved in milk ejection reflex of nursing mothers and emotional bonding
- Vasopressin/ADH - involved in the regulation of water balance and osmolarity
what is growth determined by?
growth is genetically determined, but environmental factors can influence growth (eg - nutrition, vitamins, minerals, exercise)
state 3 examples of hormones that play an important role in growth
- Growth hormone (GH) and Insulin-like growth factor 1 (IGF-1)
- thyroid hormones
- insulin
- sex hormones (testosterone + oestrogen)
- cortisol
state 3 functions of Growth Hormone (GH)
- secretion stimulated by exercise and this stimulates muscle release of IGF-1
- affects bone, muscle, adipose and liver growth and function
- stimulates protein synthesis
- major stimulus of post-natal growth
- stimulates the liver to produce IGF-1
exercise is a major stimulus of GH secretion. state 2 facts facts to expand on this statement
- different types of exercise will induce different GH responses
- responses are higher in younger individuals compared to early middle aged men
state what 3 places that GH effects during exercise
- Gluconeogenesis (liver)
- adipose tissue
- tissues
explain the effect GH has on gluconeogenesis during exercise (2 things)
- positive effect
2. increases rate of gluconeogenesis (non-carbohydrate sources –> glucose)
explain the effect GH has on adipose tissue during exercise (2 things)
- positive effect
2. triglyceride breakdown –> FFA + glycerol
explain the effect GH has on tissues during exercise (2 things)
- negative effect
2. blocks entry of glucose into tissue and increases FFA oxidation in the tissue
state the 2 main hormones used in response to stress, and where they are secreted from
- cortisol - adrenal cortex
2. epinephrine - adrenal medulla
explain the 8 step response to stress
- neural input
- hypothalamus inc^ corticotropin-releasing hormone (CRH)
- inc^ plasma CHR (in hypothalamus-pituitary portal vessels)
- anterior pituitary inc^ adrenocorticotropic hormone (ACTH)
- inc^ plasma ACTH
- adrenal cortex inc^ cortisol secretion
- inc^ plasma cortisol
- target cells for cortisol response due to inc^ cortisol
state 3 physiological functions of cortisol - responses to chronic stress
- permits epinephrine/norepinephrine action on muscles + blood vessels
- promotes glucose synthesis in liver during LT fasting or exercising
- maintaining cellular conc^ of metabolic enzymes required to produce glucose + fatty acids between meals
- dec^ events associated with inflammatory response such as capillary permeability and production of prostaglandins
cortisol and exercise - state 1 fact about it
cortisol is a catabolic hormone, therefore will act in synergy with other hormones to increase the supply of energy to the working muscles
what is the fast response to stress?
catecholamine secretion - the fast response to stress
explain the effects of ‘catecholamine secretion’ as the fast response to stress (4 facts)
- inc^ availability of energy (glucose/lipids) in the blood
- inc^ Hr, breathing frequency, + cell metabolism
- dilation of major blood vessels and constriction of peripheral capillaries
- pupil dilation
what percentage of catecholamine secreted by the adrenal medulla is epinephrine?
80% of the catecholamine secreted from the adrenal medulla is epinephrine
what is norepinephrine? and where is it usually released from?
- norepinephrine is a precursor of epinephrine, but is also a hormone in it’s own right
- released mainly by the adrenergic neurons in the sympathetic nervous system
what do both epinephrine and norepinephrine bind to?
both bind to alpha/beta-adrenergic receptors at cell membranes. the receptor type will determine the response
state the 2 main effects of norepinephrine
- inc^ HR + BP (beta 1)
2. peripheral vasoconstriction (alpha 1)
state the 5 main effects of epinephrine
- inc^ HR + BP (beta 1)
- peripheral vasoconstriction (alpha 1)
- inc^ lipid breakdown (beta 2)
- coronary dialation, bronchial dialation (beta 2)
- glycogenolysis (beta 2)
state and explain the 2 functions of the pancreas
- exocrine - secretion of pancreatic enzymes for food digestion in the duodenum
- endocrine - secretion of insulin and glucagon
the endocrine function of the pancreas is accomplished by the islets if Langerhans. state the 5 cell types as well as their proportions
- alpha cells - 10%
- beta cells - 80%
- delta cells - 3-5%
- pancreatic polypeptide cells (F/PPC) - <2%
- epsilon cells - <1%
state 2 functions of insulin
- inc^ glucose uptake + storage in adipose (lipogenesis) and muscle tissues (glycogenesis)
- inc^ glucose uptake + storage (glycogen) by liver and dec^ hepatic glucose production
- inc^ amino acid uptake and protein synthesis
- dec^ triglyceride breakdown (lipolysis) in adipose tissue
state 2 functions of glucagon
- raises conc^ of glucose in the blood by promoting glycogenolysis (glycogen breakdown)
- stimulate gluconeogenesis - the production of glucose form amino acids and glycerol in the liver
state the names of the two main insulin sensitive peripheral tissues
- skeletal muscle
2. adipose tissue
what does glucagon mainly act upon
the liver
state the 4 step pathway of how insulin works to counteract raising blood glucose levels away from homeostasis
- high blood glucose conc^ detected by insulin releasing cells in the pancreas
- insulin releasing cells of pancreas stimulated to release insulin into the blood stream
- most body cells take up more glucose
- blood glucose levels decline to a set point; stimulus for insulin secretion diminishes and body returns to homeostasis
state the 4 step pathway of how glucagon works to counteract decreasing blood glucose levels away from homeostasis
- low blood glucose levels detected by glucagon-releasing cells of the pancreas
- glucagon-releasing cells of pancreas stimulated to release glucagon into the blood; targets liver
- liver breaks down glycogen stores into glucose and releases into blood stream
- blood glucose levels rise to a set point; stimulus for glucagon release diminishes as body returns to homeostasis
state what it is meant by the key term - glycogenolysis
glycogenolysis is the breakdown of glycogen into glucose
state what it is meant by the key term - gluconeogenesis
gluconeogenesis is the metabolic process by which organisms produce sugars for catabolic reactions from non-carbohydrate sources
state what it is meant by the key term - glycogenesis
glycogenesis is the formation of glycogen from sugars
state 2 facts about type 1 diabetes
- caused by destruction of beta cells on the pancreas
2. no insulin is secreted
state 4 facts about type 2 diabetes
- environmental factors caused it
- obesity a risk factor of type 2 diabetes
- insulin secretion is normal, but it’s action is impaired
- adipose and muscle cells do not respond to the action of insulin (insulin resistance)
