Endocrine System Flashcards
What is the function of the endocrine system?
Helps control an d maintain healthy functioning of the body and its metabolic activities
What does the endocrine consist of?
Ductless glands called Endocrine gland
What is the purpose of the endocrine glands?
Secrete hormones directly into the blood
What is a hormone?
It’s a CHEMICAL SUBSTANCE carried by the bloodstream to its target tissues or organ where it REGULATES METABOLIC REACTIONS
What is the function of the hormones?
Maintain a constant internal environment
What is an endocrine gland?
Vascular, ductless gland
What is the definition of vascular?
Richly supplied with blood vessels.
How do exo and endocrine systems differ?
- EXO = secretions carried in ducts to salivary glands, liver and pancreas
- ENDO = secretions carried in blood stream to target organ
What is a target organ?
When hormones affect certain cells, and the cells that respond to a given hormone have receptor sites for that hormone
What is the hypothalamus and where is it situated?
Part of the brain , situated above the pituitary gland
What hormone does the hypothalamus secrete?
ADH- anti-diuretic hormone
What is the role of the ADH?
When there is an increase of osmolarity of the blood, hypothalamus responds and releases ADH
Why is the pituitary gland revered as the ‘master gland’?
Acts as the chemical co-ordinated of most of the other endocrine glands
What hormones are secreted by the pituitary gland?
Thyroid stimulating hormone Follicle stimulating hormone lutenizing hormone Prolactin Growth hormone
What is the function of the TSH?
Stimulates thyroid gland to secrete its hormone thyroxin
What. The function of FSH?
Females- stimulates oogenesis in the ovary
Males- stimulates spermatogenesis
What is the function of LH?
Stimulates ovulation and formation of the corpus lutem
What is the function of the prolactin?
Stimulates the production of milk after birth of baby
What is the function of the growth hormone?
Promotes skeletal and. Muscular growth
What is the growth disorder, acromegaly
Results on enlarged. Hands, jawbone and brows
What is pituitary dwarfism?
When there is a hyposecrection of growth hormone, which results in underdevelopment of the skeleton
What is the difference between hypersecretion and hyposecrection?
Hypersecretion- over secretion of a hormone
Hyposecretion - under secretion of a hormone
What is the function of the ACTH?
Stimulates adrenal cortex to secrete hormones, cortisone and aldosterone.
Where is the thyroid gland found?
Either side of the trachea , just below larynx
What hormone does thyroid secrete?
Thyroxin
What are the functions of thyroxin?
- Increases basal metabolic rate, it does this by controlling the rate of cellular respiration.
- Promote normal function on of the heart.
- Promotes normal functioning of nervous System by sharpening alertness and reflexes
How what happens when too little thyroxin occurs?
Causes low metabolic rate
What are disorders of hypothyroidism?
Cretinism - children
Myxoedema- in adults
What is cretinism
No physical growth. And immature sexual development, mentally retarded
What is myxodoema?
Results in mental and physical sluggishness , with low pressure and a slow heart and respiratory rate
What is the Endocrine system responsible for?
Responsible for chemical coordination
What is Hyperthyroidism?
producing too much thyroxin, causes high metabolic rate.
What are the symptoms of Hyperthyroidism?
Body temp is high, sweating increases
heart and respiratory rate increases.
muscle tremors and nervousness
sufferers have swollen thyroid gland - Goitre
How do you keep Thyroxin in the blood constant?
done by negative feedback
Thyroid and pituitary gland act as follows:
-pituitary detects a decreased level of thyroxin in the blood, so secretes more TSH
- TSH stimulates thyroid to secrete more thyroxin, returning back to normal level.
- The higher levelof thyroxin inhibits further secretion of TSH from pituitary
What is the purpose of negative feedabck?
ensure that the level of thyroxin in the blood is kept at the correct level (set point) at all times.
Why is the pancreas known as an unusual gland?
It functions as both an exocrine and endocrine gland
What is the function of the exocrine gland?
Secretion of pancreatic juice, which flows along the pancreatic duct into the duodenum where it helps in chemical digestion
What is the purpose of the endocrine?
Cells -islets of langerhans -secrete hormones, scattered throughout the pancreas. The hormones they secrete. Pass directly into the blood.
What are the two types of cells I islets that secrete different hormones?
Alpha and Beta cells
What hormone does Alpha cell secrete?
glucagon
What hormone does Beta cell secrete?
Insulin
What are the functions of the hormones?
Control the level of blood sugar/ glucose in the blood
What is the normal level of glucose concentration?
3.5- 5.5 mmol/litre of blood.
What is glucose?
Simple sugar formed from intake of carbs.
Primary source of cellular energy
How is glucose transported as it’s not water soluble?
Transported with the aid of insulin.
What are the functions of the hormones in the bloodstream?
Insulin- lower blood sugar(glucose) level
Glucagon - raises. Blood sugar level
How does insulin lower blood sugar levels?
-when glucose is absorbed and moves into blood,it will increase blood glucose levels above set point. As blood passes through pancreas, beta cells detect raised glucose levels and respond by secreting insulin
- insulin goes to muscles and liver to:
- make cells permeable to glucose, can leave blood , to enter cells
- increasw rate which glucose converted into glycogen.
- with process of taking glucose out of blood, blood sugar levels are lowered
- the lower glucose level is detected, by beta cells, which then stop releasing insulin into blood.
How does Glucagon increase blood glucose levels.?
- waking up, glucose level I. Blood is low.
- as this blood passes through pancreas,alpha cells detect low glucose levels and respond by secreting glucagon into the blood
- in the liver cells, glucagon causes breakdown of glycogen into glucose
- As a result, liver releases glucose into blood, increasing blood glucose level.
- the increased glucose level detected by alpha cells, which then stop releasing glucagon into the blood.
What are the adrenal glands
pyramid shaped glands
found on top of each kidney
Each adrenal gland is made of two glands, inner medulla and outer cortex.
What is the purpose of the cortex?
secrete steroid hormones:
Aldossterone
Cortisone
reproductive hormones
what is the function of Aldosterone?
regulate the electrolytic levels of body fluids and is therefore vital fpr omoregulation
How does Aldosterone help to regulate electrolyte?
increased reabsorption of sodium ions
What is the function of cortisone?
increases body ability to resist stress.
also an anti-inflammatory and anti-allergic
What hormone does the adrenal medulla secrete?
Adrenalin
What are the effects of adrenalin?
‘fight or flight’ hormone, secreted under situation of danger or excitement,will prepare body for action, so an cope with emergency.
What effects does Adrenalin bring about?
- Blood pressure is increased,for blood to go to skeletal and cardiac mucles
- Blood levels increased, glycogen converted to glucose, provide fuel for release of more energy
- Oxygen content raised, breathing rate and depth of breathing increased. oxygen needed for increased respiration,more energy.
- Heart rate is increased
- muscle tone increased,muscle respond quickly.
What are some of the other effects of adrenalin?
- Dilation of pupils , for better vision
- increased sweating
- Reduction of digestive system activity
- Increased mental alertness.
