The Endocrine System Flashcards
What two systems do body systems use to communicate with each other?
Endocrine system
Nervous system
What are the two branches of the ANS? What sort of activities does each branch control?
Sympathetic (fight or flight)
Parasympathetic (rest and digest)
What is the term for a slow heartbeat? What is the term to describe a fast heartbeat?
Bradycardia
Tachycardia
How do sympathetic nerve fibres affect blood vessels?
Cause constriction of of all blood vessels —> except capillaries and precapillary sphincters
What organs are prioritised with blood supply in a flight or fight situation?
Brain
Heart
Skeletal muscle
What is a benefit of venoconstriction in a fight or flight situation?
It will increase blood return to the heart
Where are 3 places in the body neurocrine communication is used?
Hypothalamus
Posterior pituitary
Adrenal medulla
What is neurocrine communication?
Secretion of substances into the blood by a neurone to other target cells
The thymus is a example of which sort of gland?
Endocrine gland
How does the thymus develop?
Full formed and functional at birth
Mostly fat by late teens
What is the main function of the thymus? What hormone does the thymus produce? What does this do?
Thymic cell education
Thymosin - promotes t cell maturation
What 3 different type of hormones exist? Where is the target of each at the cell?
Steroid hormones - cytosolic/nuclear
Peptide hormones - cell membrane
Catecholamines - cell membrane
What is the relevance of the hypothalamus with relation to the nervous system and endocrine system?
Its the point where the CNS and endocrine system communicate
What hormones are produced at the hypothalamus that travel to the posterior pituitary?
ADH and oxytocin
How do hormones travel from the hypothalamus to the anterior pituitary?
Via the hypothalamo-hypophyseal portal system
What is another name for the pituitary gland? Where is it located in reference to the hypothalamus? What is its structure?
The hypophysis
On a stalk below the hypothalamus
Two lobes - anterior and posterior
What hormones are released by the thyroid gland? What does it do?
Thyroxin - controls metabolic rate
Where are the adrenal glands located in the body? What sort of structure do they have?
Above each kidney
Cortex and medulla structure
What two categories can adrenal cortical hormones be separated into?
Glucocorticoids
Mineralocorticoids
What is an example of a glucocorticoid?
Cortisol
What is an example of a mineralocorticoid?
Aldosterone
Where is the pineal gland located in the body?
It is a midline structure in the brain
What hormone does the pineal gland produce? What does it do?
Melatonin involved in the control of Circadian rhythm - inhibits the release of gonadotropins
Why is the pineal gland not visible on skull X-rays?
Calcifies in early adulthood
What is the difference between the ANS and somatic nervous system with regards to nerves that go from the CNS to effectors?
The ANS has two neurones
The somatic nervous system has one neurone from CNS to effector
Where are the cell bodies of presynaptic neurones in the ANS?
In the CNS
Where are the cell bodies of the post synaptic neurones in the ANS?
Peripheral ganglion
What are chromaffin cells? Where are they found?
Adrenal medulla
Effectively, modified postsynaptic neurones
What cause chromaffin cells to release their secretory products? What are the secretory products of chromaffin cells?
A nerve impulse from a myelinated presynaptic neurone
Adrenaline/Noradrenaline
What types of neurotransmitter/hormone are adrenaline/noradrenaline?
Catecholamines
The release of adrenaline and noradrenaline from chromaffin cells is an example of which type of secretion?
Neurocrine secretion
What are some examples of the effects of adrenaline/noradrenaline?
Increased blood pressure
Increased blood glucose (glycogen –> glucose)
Increased breathing rate
Increased metabolic rate
