Endo Intro to endocronology Flashcards
What is homeostasis?
Maintenance of a steady state/internal
environment
What elements stimulate hypothalamus if there is a change in temperature?
-Cutaneous temperature receptors
-Hypothalamic temperature receptors
What is done to counter heat loss?
sweating,
vasodilatation
What is done to counter heat gain?
shivering,
vasoconstriction,
metabolism
What happens to the set point when the body has an infection?
With infection the set point
is changed and body
temperature rises
What are the benefits of an increase in body temperature during an infection?
– Inhibits bacterial growth
– Speeds up metabolic reactions
– Increases delivery of white blood cells to infection sites
What is the homeostatic control of blood pressure?
- Medulla signals to heart and peripheral resistance
- Baroreceptors(stretch receptors) signal the medulla tor control blood pressure with negative feedback.
What does hypertension do that causes an increase in blood pressure?
Resetting the
sensitivity of the
baroreceptors
What is the control of circulating cortisol concentrations?
- Hypothalamus secretes corticotropin releasing hormone which acts on the anterior pituitary gland.
- This leads to the secretion of ACTH that acts on the adrenal cortex resulting in the release of cortisol.
- Negative feedback acting on the hypothalamus control circulating cortisol concentrations
What are the effectors that are involved in circulating cortisol concentrations?
- Anterior pituitary gland
- Adrenal cortex
What increases set point in control of circulating cortisol concentrations?
- Stress
- Circadian rhythm
How does the positive feedback control system work in haemostasis?
- Break or tear in blood vessel wall
- Clotting occurs as platelets adhere to site and release chemicals
- Released chemicals attract more platelets
- Clotting proceeds until break is sealed by newly formed clot
How does the positive feedback system in the control of uterine contractions in labour work?
- In labour oxytocin
stimulates contraction
of uterine muscles - Cervix dilates and
activate stretch
receptors - Action potentials
signal to
hypothalamus - Stimulates further
release of oxytocin
What are major endocrine glands?
- Hypothalamus
- Pituitary gland
- Thyroid, adrenal cortex, gonads
- Pancreas
- Parathyroid glands
What does the hypothalamus secrete?
Releasing & inhibiting hormones
What does the anterior lobe of pituitary gland secrete?
Trophic hormones
What does the posterior lobe of the pituitary gland secrete?
oxytocin & vasopressin (ADH)
What does the thyroid gland secrete?
Thyroxine, tri-iodothyronine
What does cortex of the adrenal gland secrete?
Cortisol, aldosterone