Endocrine Flashcards
What does the endocrine system do
Release hormones into the bloodstream
Functions of the endocrine system- Regulates fluids and electrolytes
3 hormones that regulate fluid and electrolyte blanace:
* ADH
* Aldosterone produced from cortex
* Atrial natriuretic peptode (ANP) produced by the heart.
Functions of the ES- Coordinates the response to stress
When stressed hypothalamus signals the pituitary gland to produce hormones which signals the production of adrenal gland to increase produce cortisol
Functions of ES- Regulates growth and metabolism
Thyroid galnds secretes thyroxin and triidothyronine. These stimulate growth, reproduction, development and metabolism.
Functions of ES- Regulates reproduction
Endocrine glands in the reproductive system produce sex hormones such as testesterone and oestrogen.
Difference between Endocrine glands and exocrine glands
Endocrine:
* Secrete hormones into the bloodstream
* No ducts
* Communication
Exocrine glands
* Secrete hormones into cavity or to skin
* Has ducts
* Digestion/lubrication/ protection
Examples of Exocrine glands
Prostate gland
Mucous glands
Salivary glands
Example of exocrine and endocrine glands in action in liver and pancreas
Exocrine:
Secretion of bile and pancreatic juices into the GI tract
Endocrine:
Secretion of insulin and glucagon into the blood stream.
Homeostatic control centres of the endocrine system
Hypoythalamus- gland in brain which controls hormone system. It releases hormones to pituitary gland which secretes them to organs
Pituitary gland
Master gland. Tells other glands to release hormones
Individual endocrine galnds
Parts of the pituitary glands
Anterior lobe of the pituitary produces 7 peptide hormones
Posterior lobe of the pituitary produces ADH and Oxytocin
Hormones of the Anterior pituitary glands
Stimulate other endocrine glands to produce:
ACTH (adrenocorticotrophic hormone) –> Adrenal gland
TSH (thyroid stimulating hormone) –> Thyroid gland
FSH/LH follicle stimulating hormone/luteinising hormone → gonads
Or specific target tissues
PL prolactin → breast
* MSH melanocyte stimulating hormone → skin pigment
* GH growth hormone → muscle/bone
Hormones of the posterior piyuiatary gland are..
Made in hypothalamus
Carried to the posterior pituitary
Released into the blood stream
e.g.
Oxytocin → uterus contraction
→ lactation
- ADH antidiuretic hormone → kidney (collecting ducts)
What determines the size of the response
Number of receptors
Concentration of the hormone
How are hormones regulated
Production:
Response to environmental challenge
Part of hormone cascade (negative/positive feedback)
Circadian rhythm
Loss:
Urine
Bile
Uptake by target tissue
Liver breakdown
Hormone regulation- permissive
Where a hormone requires the previous effect of another hormone
e.g.
* Oestrogen = then progesterone on the uterus
Hormone regulation- Antagonistic
Where two or more hormones oppose the effects of each other- antagonistic effect
e.g.
Blood glucose
* insulin causes blood glucose level to decrease
* glucagon causes blood glucose level to increase
Hormone regulation- Synergistic
Two or more hormones complement each other simultaneously:
- Example:
- Milk production requires…
- oestrogen
- progesterone
- prolactin
- oxytocin
…at the same time
Hormones required for reproduction
FSH/LH from pituitary
* oestrogen
* Progesterone
* testosterone
* prolactin - milk duct development
* oxytocin - birth and lactation
Pancreatic function
Contains islets of langerhans which secrete insulin and glucagon
They have 3 types of cells:
1) Alpha cells- secrete glucagon
2) Beta cells- secrete insulin
3) Delta cells- secretes digestive enzymes
How insulin works
Stimulates the uptake of glucose to cells.
Conversion of gluocse into glycogen
stimulates entry of amino acis into cells and the synthesis of proteins
Decreases glycogenolysis and gluconeogenesis
Insulin binds to insulin receptors on cell membranes which allows for the GLUT4 channels to open so glucose can enter cells
How Glucagon works
Glucagon is a hormone whose principle role is to increase blood glucose
levels when it falls below normal
* High glucose levels cause glucagon release to be inhibited
* Low glucose levels promote glucagon release, particularly in the liver
1.Glycogenolysis -the breakdown of glycogen to glucose
2.Gluconeogenesis -the formation of glucose from glycerol and proteins
rather than carbohydrates
Stress response
initated by CNS and endocrine system
Corticotropin-releasing hormone (CRH) is released from
1. hypothalamus
2. sympathetic NS
3. pituitary gland
4. adrenal gland
The activation of these systems redirects adaptive energy to the CNS and stressed body sites
Types of diabetes
Type 1- no insulin
Type 2 - Insulin resistance
Central stress response
sympathetic NS is aroused during the stress response and causes medulla of the adrenal glands to release catecholamines into the blood stream
CRH stimulates pituitary gland to release variety of hormones including :
1) ADH and oxytocin
2) prolactin, endorphins, growth hormones and ACTH
ACTH stimulates the cortex of adrenal galnd to release cortisol
Cortisol role
prodcued in the adrenal cortex within the adrenal gland
released in response to stress and low Blood sugar
It functions:
1. increase blood sugar through gluconeogenesis
2. Suppress the immune system
3. Aids in the metabolism of fat, protein and carbohydrates
4. Decreases bone formation
5. Increased blood pressure
stages of sleep
Stage 1 light sleep, easy to wake, hallucination (hearing doorbell, seeing flash, falling sensation, images of the day)
Stage 2 harder to waken, K-complex, long term memories
Stage 3 and 4 very difficult to waken, sleep walking/talking
REM paradoxical sleep, eye movement, faster pulse, faster
breathing and brain active but skeletal muscle paralysis, dreaming
Serotonin and Melatonin
The sleep wake cycle (body clock) is located in the suprachiasmatic
nucleus. It is sensitive to light.
* The pineal gland secretes serotonin during the day and
melatonin during the night.
Sleep
Two major regulatory principles are involved:
* Homeostasis
* Circadian organization
Cortisol secretion has a circadian rhythm:
* Very low during the night (low stress)
* Raised during the day (stress)
Consequences of sleep deprivation
Mental health:
Stress
Anxiety
Depression
CVD:
Angina pectoris
Hypertension
Reproductive effects
Spontaneous abortion
Low birth weight
Prematurity
Circadian rhythm disruption
Menstrual cycle
Respiratory rate
Body temp
