endocrine physiology Flashcards
What is the difference between diabetes mellitus & diabetes insipidus?
Diabetes mellitus = high blood glucose
Diabetes insipidus = due to ADH levels (kidneys can’t concentrate urine)
What type of control is fast acting & short-lasting?
Control via nervous system
- Fast acting bc of nerve impulses
- Short lasting bc NTs are removed from synaptic cleft asap
Explain control via the endocrine system
Controls tissues via hormones which are transmitted through the blood & tissue fluids. Hormones act on target tissues
What type of control is slow acting, and long-lasting?
Control via endocrine system
- slow acting bc hormones need time to get released & to get to the target tissue
- long-lasting bc hormones stay in the bloodstream longer
Name two ways that the endocrine system is controlled?
- Nervous system
- Endocrine system
How do hormones act on tissues?
- target tissues have a receptor
- hormones will only act on specific target tissues if they have the corresponding receptor
List the three categories of hormones
- Steroid hormones
- tyrosine derivatives
- protein hormones
Where are steroid hormones secreted from?
give examples of each
- adrenal cortex = cortisal, aldosterone
- testes = testosterone
- ovaries & placenta = estrogen, progesterone
What is the composition of steroid hormones?
cholesterol-based
* made of sterol rings
Where are tyrosine derivatives secreted from?
give examples of hormones
- thyroid gland = T3 & T4
- adrenal medulla = epinephrine & norepinephrine
Where are protein hormones secreted from?
give examples of hormones
3 P’s
1. pituitary = ACTH, GH, TSH, ADH, oxytocin
2. parathyroid = PTH
3. pancreas = insulin, glucagon
List the 3 types of control of endocrine secretion
- neural control
- endocrine control
- humoral control
Explain neural control
endocrine secretion
- autonomic nervous system (ANS) directly stimulates the endocrine gland
- endocrine gland secretes hormone
- secretion stops when there are sufficient levels of hormone or when levels get too high
Ex. adrenal medulla releases NE & E when stimulated by ANS
How are hormone levels regulated?
type of feedback
Negative feedback
Explain endocrine control
endocrine secretion
- uses tropic hormone to stimulate endocrine gland
- 2 glands & 2 hormones
- endocrine gland A releases tropic hormone
- tropic hormone stimulates endocrine gland B
- endocrine B releases hormone
Ex. TSH stimulates thyroid gland to release T3 & T4
Explain humoral control
endocrine secretion
- endocrine tissue senses blood levels (internal environmental stimulus)
- internal stimulus is sensed by endocrine gland
- endocrine gland releases hormone
ex. high blood sugars are sensed by pancreas –> pancreas releases insulin to lower blood sugar
What is the hypophysis?
- pituitary gland
- location: cranial floor (base of skull)
- size = very small –> has an anterior & posterior lobe
How is the hypothalamus connected to the pituitary gland?
via the pituitary stalk
What is the neurohypophysis?
- posterior lobe of the pituitary gland
- directly connected to the hypothalamus via **hypophyseal tract **
- composed of nerve tissue
What is the adenohypophysis?
- anterior lobe of the pituitary gland
- made of glandular epithelium
What hormones does the anterior pituitary secrete?
state the function of hormones
FLAT GP hormones
FSH = sperm & follicle development
LSH = testosterone & ovulation
ACTH = adrenal cortex
TSH = thyroid gland
GH = growth hormone
Prolactin = milk production
Which hormones secreted from the anterior pituitary are tropic hormones?
TSH –> stimulates thyroid gland to produce T3 & T4
ACTH –> Sstimulates thyroid gland to secrete epinephrine & norepinephrine
What hormones does the posterior pituitary secrete?
state the function of hormones
neurohormones (bc of neural tissues)
- ADH = for water retention
- oxytocin = birthing process/uterine contractions; milk secretion
How is the anterior pituitary controlled?
via the hypophyseal portal system