Endocrine system Flashcards
What is the endocrine system
The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs.
Name 4 functions of the endocrine system?
Homeostasis Release hormones to: Regulate metabolism Growth and development Sleep regulation Sexual function Reproduction Mood regulation Tissue function Blood pressure regulation
Name 3 types glands in the endocrine system
Pituitary Adrenal Thyroid Parathyroid Ovaries/ Testes Pancreas?
What are hormones?
Chemicals released by glands that travel through the bloodstream to reach organs to exert an effect
How is hormone secretion controlled?
By negative and positive feedback
What is positive feedback
When a gland detects an increase in hormone levels that results in even more secretions to complete an action
i.e: oxytocin release in childbirth to aid contractions
What is negative feedback
When glands detect an increase in hormone levels causing them to decrease the amount they are secreting
What are the 3 types of hormones
Steroids
Armines
Proteins
What part of the brain controls the endocrine system?
The hypothalamus
Where is the hypothalamus located?
At the base of the brain
What is the pituitary gland
The endocrine’s ‘master gland’ - receives information from the hypothalamus and releases the necessary hormones
Where is the pituitary gland located?
It is a small bean shaped gland at the base of the brain, just below hypothalamus
What is the function of the pineal gland?
To release melatonin for sleep regulation
What is the main function of the thyroid gland?
To release thyroid hormone for metabolic regulation
What happens if someone has hypOthyroidism?
Their thyroid gland doesn’t produce enough thyroid hormone - can cause slow heart rate, constipation, weight gain, slow movement
What happens if someone has hypERthyroidism
Their thyroid gland produces too much thyroid hormone Heart rate increases Diarrhea Weight loss Irritability Matted fur
Which organ makes glucagon and insulin?
Pancreas
Which organ makes estrogen and progesterone?
Ovaries
Which organ makes testosterone?
Testes
name 2 hormones released by the anterior pituitary gland and their functions
Any of:
- ACTH – adrenocorticotrophic hormones – targets agrenal gland cortex, stimulates release of corticosteroids and mineralocorticoids
- FSH – follicle stimulating hormone – Sertoli cells in male testes causes spermatogenesis and female growth follicles
- GROWTH HORMONE – tissue growth and fat deposition
- LH – Luteinizing hormone – ovaries, ovulation and corpus luteum development, male production of testosterone
- PROLACTIN – targets mammary glands, stimulate development and mild let down
- TSH – Thyroid stimulating hormone – causes thyroid gland – produces thyroxine, controls metabolic rate
Name 2 hormones produced by the posterior pituitary gland and their functions
- ADH – Antidiuretic hormone / vasopressin – targets distal convoluted tubule in kidney – increases resorption of water, thus increasing plasma volume, info from baroreceptors trigger secretion
- OXYTOCIN – targets uterus during parturition (childbirth) and muscles in mammary glands resulting in milk let down (lactation)
Name 4 hormones and their functions
Melatonin - sleep regulation
Oxytocin - contractions during childbirth, menstrual regulation
Thyroid hormone - metabolism regulation
Growth hormone - growth
ADH - increases absorption of water
Cortisol - increases glucose in bloodstream to enhance brain’s use of glucose in fight or flight mode
Insulin - reduces blood glucose levels
Glucagon - increases blood glucose levels
LH - controls estrogen and testosterone production
Where is the pineal gland located?
In the brain - specifically deep in the epithalamus (middle of the brain just above the thalamus)
What stimulates melatonin secretion from the pineal gland
Daylight length / photoperiod
Which gland triggers hibernation?
Pineal gland (secretes melatonin in response to daylight length)
Where is the thyroid located?
In the trachea - caudal to larynx
What is the thyroid gland comprised of?
Follicles
Where are C cells found and what do they produce?
Found in between thyroid follicles
They produce calcitonin
What does calcitonin do?
decreases blood calcium
Which gland produces calcitonin?
Thyroid
Which gland produces adrenaline
Adrenal glands
Where are adrenal glands located?
On top of both kidneys
Where is the parathyroid gland located?
Near to the thyroid gland
What does the parathyroid gland produce?
Parathyroid hormone - to increase blood calcium
Which hormone increases blood calcium?
Parathyroid hormone
Which 2 hormones control blood calcium levels?
Calcitonin - decreases
Parathyroid hormone - increases
Which hormone do the kidneys produce?
Erythroprotein
What is the function of erythroprotein and where is it secreted?
Kidneys
Function = the stimulate red blood cell production in bone marrow
What are the adrenal glands divided into?
The cortex and medulla
Which hormones come from the medulla of the adrenal glands?
Adrenaline and noradrenaline
What is the function of adrenaline and noradrenaline?
Adrenaline = prepares body for fight/flight by maximising blood glucose levels
Noradrenaline = the neurotransmitter of the sympathetic nervous system to increase heart rate etc
What hormones does the adrenal gland cortex secrete?
- Mineralcorticoids (i.e: aldosterone) – controls sodium and potassium levels
- Glucorticoids (cortisol) – sex hormones
Which part of the pancreas is involved in the endocrine system?
Islets of Langerhans
Where are alpha and beta cells found?
In the pancreas - specifically the islets of Langerhans
What do alpha and beta cells produce?
Alpha - glucagon
Beta - insulin
Where is the pancreas located?
it a long, flat gland that lies horizontally behind your stomach
What is the function of the pancreas?
Plays a role in digestion and regulating blood sugar levels by secreting insulin and glucagon
How does the pancreas regulate blood sugar levels?
When food is eaten, carbs are converted to glucose
Glucose is absorbed into bloodstream, increasing blood sugar levels
This increase signals the pancreas to produce insulin (from beta cells)
Insulin triggers cells to take in glucose from bloodstream so blood levels drop
4-6 hours after eating, low blood sugar triggers pancreas to produce glucagon
Glucagon signals to liver and muscles to convert stored glycogen into glucose
Glucose is released back into bloodstream to be used by cells for energy
What are prostaglandins?
A group of lipids made at sites of tissue damage or infection that are involved in dealing with injury and illness. They control processes such as inflammation, blood flow, the formation of blood clots and the induction of labour.
What do prostaglandins do?
Sustain homeostatic functions and mediate pathogenic mechanisms (including inflammatory response)
Which group of lipids mediates the inflammatory response
Prostaglandins
