5 - Endocrine Glands Flashcards
What endocrine glands are found in the brain?
- Hypothalamus
- Pituitary Gland (anterior + posterior)
- Pineal Gland
What hormones come from anterior pituitary?
- GH
- TSH
- Adrenocorticotropic - ACTH
- FSH
- LH
- PRL
**all tropic hormones except for prolactin
What are the major hypothalamic hormones?
The hypothalamus hormones are “tropic factors” for pituitary gland
What are the main components of the negative feedback control?
- Hypothalamus
- Pituitary Gland
- Endocrine Gland
What does GH do?
Stimulates growth and cell reproduction in humans
and other animals.
by:
- Stimulating growth of soft tissues (increase # of cells, prevents apoptosis, increase size of cells, inhibits protein degradation) and skeleton
Secreted by anterior pituitary Regulated by: 1. GHRH 2. GHIH 3. Insulin like growth factors
What’s the metabolic effect of GH?
- Increased rate of protein synthesis in all body cells.
- Increased fatty acid mobilization from adipose tissue.
- Increased fatty acid use by body tissues.
- Decreased rate of glucose/glycogen use by body tissues.
What are the primary functions of the pineal gland?
- Helps keep body’s circadian rhythms in synchrony with light-dark cycle
- Promotes sleep
- Influences reproductive activity, including
onset of puberty - Acts as antioxidant to remove free radicals
- Enhances immunity
Where are the adrenal glands located? What do they do?
Above the kidneys
Adrenal glands produce hormones that help regulate your metabolism, immune system, blood pressure, and response to stress
ex: Epinephrine, cortisol, aldosterone
Where is the thyroid gland?
Two lobes of endocrine tissue in the neck. Controls metabolism.
The cells are follicular and arranged into hollow spheres.
Produces two iodine containing hormones:
- Tetra iodothyronine (T4 or thyroxine)
– Tri-iodothyronine (T3) **most active form
What are T3 and T4?
- Two main thyroid hormones: T3 and T4
- T3 and T4 work together to regulate how your body uses energy
What gland controls the release of hormones from the anterior and posterior pituitary glands?
The hypothalamus!
What hormones does posterior pituitary release?
- Vasopressin (urine formation)
- Oxytocin (uterine contract, milk ejection)
What is a cause of dwarfism?
- Hyposecretion of GH in child
due to pituitary or hypothalamic dysfuntion
What’s the Suprachiasmatic Nucleus?
- Body’s master biological clock
- SCN is set daily by external cues
- Melatonin plays a role here (higher when dark, lower during the day)
- Located in hypothalamus
What are conditions that result from abnormalities in the thyroid?
- Hypothyroidism (aka myxedema)
- Primary: failure of thyroid
- Secondary: deficiency of TFH, TSH or both
- not enough dietary iodine
- Hyperthyroidism (aka Graves disease)
Describe the generalized stress response.
- Stressor triggers hypothalamus:
1. Activation of sympathetic nervous system (Epinephrine secretion) - Elevation of blood glucose and fatty acids
2. Activation of CRH-ACTH-Cortisol system
3. Maintenance of blood volume/pressure (more aldosterone and vasopressin)
What gland starts the fight or flight response?
- Hypothalamus
- It secretes CRH to stimulate ACTH and cortisol and triggers vasopressin release
- It stimulates the sympathetic nervous system which brings about the secretion of epinephrine
What does aldosterone do?
Increases the retention of sodium and water and to increase the excretion of potassium by the kidneys (regulates sodium homeostasis)
Secreted by zona glomerulosa of adrenal gland
What does cortisol do?
- Inhibits glucose uptake (except not for the brain)
- Key role in stress
- Stimulates protein degradation
- Follows diurnal pattern of ACTH
- Cortisol is a permissive hormone
Overall metabolic action: Increase blood glucose concentration at the expense of protein and fat stores (Gluconeogenesis, Lipolysis, inhibits glucose uptake)
How does cortisol use negative feedback?
- Directly inhibits secretion of CRH from hypothalamus
2. Inhibits the action of CRH on the anterior pituitary
What does the adrenal medulla do?
- Releases epinephrine and norepinephrine
(secreted into blood by exocytosis) - Epinephrine increases blood glucose and blood fatty acids
