endocrine system Flashcards
(19 cards)
What is a hormone?
A hormone is a chemical messenger released by a gland into the blood that affects target organs.
Name the gland that controls other glands in the endocrine system.
The pituitary gland (also called the “master gland”).
What hormone does the pancreas produce to lower blood glucose levels?
Insulin.
How does insulin lower blood glucose?
Insulin causes glucose to move from the blood into cells and is stored as glycogen in the liver and muscles.
What hormone is released when blood glucose is too low?
Glucagon.
What is negative feedback?
: A mechanism where a change is detected and corrected to maintain stable internal conditions.
Describe how glucagon increases blood glucose levels.
Glucagon causes glycogen in the liver to be broken down into glucose and released into the blood.
Explain how negative feedback controls thyroxine levels.
If thyroxine levels fall, the pituitary gland releases more TSH, stimulating the thyroid to release thyroxine. If thyroxine levels are high, TSH release is inhibited, so less thyroxine is made.
What hormone is produced by the adrenal glands and what is its effect?
Adrenaline; it prepares the body for “fight or flight” by increasing heart rate and blood flow to muscles.
How is the hormonal system different from the nervous system?
Hormonal responses are slower, act for longer, and use chemical messages in the blood. Nervous responses are faster, short-lived, and use electrical impulses in nerves.
what are the main organs
pituitary gland
pancreas
thyroid
adrenal gland
ovary
testes.
what does Pituitary Gland (in the brain)
Known as the “master gland” — it controls other glands. For example:
* TSH tells the thyroid to release thyroxine
* LH and FSH control the menstrual cycle and puberty
* ADH controls water balance
what does Pancreas (near the stomach) do?
Regulates blood glucose:
* Insulin lowers blood sugar
* Glucagon raises blood sugar
what deos Thyroid (in the neck)
Controls metabolic rate, heart rate, temperature, growth. Uses negative feedback via TSH from the pituitary
what does Adrenal Glands (on top of the kidneys)
Released in stressful or dangerous situations (“fight or flight”):
* Increases heart rate
* Boosts glucose to muscles
* Prepares body for action
Ovaries (females)
Control menstrual cycle, puberty, and support pregnancy.
* Oestrogen thickens uterus lining
* Progesterone maintains uterus lining
What is the human endocrine system made up of?
Endocrine system is made up of glands that release chemicals called hormones direclty to the blood stream
difference between nervous system and hormone
The nervous system sends messages using electrical impulses through neurons.
Nervous system responses are very fast (milliseconds) and short-lasting.
Signals travel to specific target cells, making responses precise.
It controls quick actions like muscle movement and reflexes.
Hormones are chemical messengers released into the bloodstream.
Hormonal responses are slower (seconds to minutes) but last longer.
Hormones can affect many cells in the body that have the right receptors.
They regulate slower processes like growth, metabolism, and reproduction.
Types of endocrine Glands
Pituitary gland (master gland controlling other glands)
Thyroid gland (controls metabolism)
Adrenal glands (produce adrenaline)
Pancreas (produces insulin and glucagon)
ovaries (iThey produce female sex hormones like oestrogen and progesterone, which control the menstrual cycle)
Testes . They produce the male sex hormone testosterone, which controls the development of male secondary sexual characteristics (like facial hair and deeper voice
