Chapter 14 Hormones Flashcards
What is an endocrine gland?
A group of cells which are specialised to secrete hormones directly into the blood stream
What is an exocrine gland?
A group of cells which are specialised to secrete chemicals into ducts and to body surfaces
What is a hormone?
Chemical messengers which travel around the body in the blood stream
What are some examples of glands and the hormones they secrete?
Pituitary- Master Gland, stimulating e.g FSH, growth hormones, ADH
Thyroid- Thyroxine, contrast rate of metabolism
Ovaries/Testes- Oestrogen/Testosterone for secondary sex characteristics
What types of compounds can hormones be?
Steroids, Proteins, Glycoproteins, Polypeptides, Amines, or Tyrosine Derivatives
What are target cells?
Target cells contain receptors specific to a certain hormone, having a complementary shape, on the cell surface membrane or in the cytoplasm
What are the steps from when a hormone is produced to meeting the target cell?
Hormones are secreted into the blod stream from the gland when stimulated e.g by a nerve impulse
The hormone is transported in the blood plasma and diffuses out of the blood to bind to the complimentary glycoprotein receptor at the target cell
How do steroid hormones elicit a response? Give an example of a steroid hormone
Steroid hormones are lipid soluble, meaning they can pass through the cell surface membrane
They bind to their complimentary receptor in the cytoplasm or nucleus of the cell
The hormone-receptor complex acts as a transcription factor of the desired gene, causing transcription to begin, end, amplify, or dampen.
E.g Oestrogen
How do non-steroid hormones elicit a response? OCR. Give an example of a non-steroid hormone
Non-Steroid hormones are water soluble, so hydrophilic, so cannot pass through the cell surface membrane
They bind to a complementary receptor in the phospholipid bilayer
Changes to internal protein which activates adenylyl cyclase
Catalyses the conversion of ATP into cAMP
cAMP activates PKA, which can phosphorylate and activate enzymes for a cellular response
E.g Adrenaline
Compare hormonal and neuronal communication
Hormones vs nerve impulses
Bloodstream vs Neurones for transmission
Slow vs Fast
Widespread vs Specific
Long lasting vs short lived
Can be permanent vs temporary
Where is the adrenal gland located? What are the components of the adrenal gland?
On top of the kidney
Outermost layer= Capsule
Outer layer= Adrenal Cortex
Inner Layer=Adrenal Medulla
What types of hormones does the adrenal cortex secrete?
(Vital to life)
Glucocorticoids
Mineralocorticoids
Androgens
What hormones are glucocorticoids and what do they control?
What controls the secretion of these?
Cortisol regulates metabolism of the cell by controlling how fats/ proteins/ carbohydrates are converted to energy.
Helps regulate blood pressure and cardiovascular response to stress
Corticosterone + Cortisol regulates immune system and suppresses inflammation
Controlled by the hypothalamus
What hormones is a mineralocorticoid and what does it control?
What controls the secretion of this?
Aldosterone- controls blood pressure by controlling balance of salt/water in blood and body fluids
Release controlled by signals from the kidney
What are androgens and their role?
Male/Female sex hormones which are released in small amounts
Particularly important during menopause
Impact minimal compared to Oestrogen/Testosterone
What hormones are secreted by the adrenal medulla? When are they secreted?
Adrenaline and Noradrenaline
Released in times of stress, when the sympathetic nervous system is stimulated
What is the impact of adrenaline?
Increases heart rate
Divert blood to muscles and the brain
Converts glycogen to glucose in the liver, increasing blood glucose concentration (for increased respiration)
Increase breathing rate
(Works with noradrenaline)
What is the impact of noradrenaline?
Increasing heart rate
Widening pupils
Widening air passages of the lung
Narrowing blood vessels to non-essential organs, thus increasing blood pressure
(Works with adrenaline)