Endocrine System Flashcards
What are the 2 main functions of the endocrine system?
Communication and control - in response to external environment
Maintenance of homeostasis - constant internal environment
Which of the endocrine or nervous responses lasts longer and which acts faster?
The endocrine system is not as quick to act, however, can be much longer-lived, whilst the nervous system responses can be almost immediate, yet do not persist.
What are the three ways a hormone can communicate with a target cell?
- Autocrine
- Paracrine
- Endocrine
Explain Autocrine communication.
This involves a cell producing a\the hormone which then acts on the same cell.
Explain Paracrine communication.
This involves a cell producing the hormone that acts on other cells nearby.
Explain Endocrine communication.
This involves a hormone being secreted into the bloodstream by a specialised ‘endocrine gland’, this then travels to multiple sites throughout the body.
What are the three main categories of hormones?
Peptides/proteins, steroids and amines.
List the three main categories of hormones in order from smallest to largest.
Amines, steroids, peptides/proteins.
How soluble are peptides/proteins and how do we administer them?
Readily soluble (water) and can get broken down by stomach acids therefore usually injected.
What are some examples of peptides/proteins that are administered to humans/animals?
- Insulin
- Growth hormones
How soluble are Steroids and how do we administer them?
Somewhat soluble (not water but is in fats). mainly administered by injection to muscle, skin cream or implant beneath the skin as cannot be injected to the bloodstream due to fat solubility.
What are some examples of steroids that are administered to humans/animals?
- Hydrocortisone
- Progesterone
How do we administer Amines? What is the issue with using these as opposed to the other 2 main hormone types?
Generally orally, used to treat amino acid deficiencies such as the one that results in thyroid issues.
The main issue with amine’s is that they are harder to predict the outcome due to their chemical structure.
What are trophic hormones?
They are messenger hormones that are released from the pituitary gland and travel to other glands to signal production of another hormone at those sites.
What is an example of a trophic hormone?
Thyroid-stimulating hormone (TSH)
This gets emitted from the pituitary, then travels to and stimulates the thyroid glands to produce thyroxine.
What is an ‘episodic’ hormonal rhythm?
Bursts of release
EG: Growth Hormone
What is a ‘diurnal’ hormonal rhythm?
A day/night cycle
EG: Cortisol.
Rises early in the morning and decreases throughout the day, remains low at night. (Reversed for nocturnal animals).
What is a ‘seasonal’ hormonal rhythm?
Responds to environmental changes with the seasons
Can be triggered by the changing lengths of day or the temperature of the seasons etc
EG: Melatonin, responds to changing daylengths and peaks in Autumn
Briefly explain how the hypothalamus monitors and controls hormone release.
Receptors in the hypothalamus sense concentrations of the hormones, when they receive a weak signal, they produce more releasing factor and vice versa for a strong, more inhibitory factor.
List the 8 important endocrine glands.
- Pineal gland
- Hypothalamus
- Pituitary gland
- Thyroid glands
- Parathyroid glands
- Gonads
- Adrenal gland
- Pancreas
What is the main function of the Pineal gland?
Controls the sleep/wake cycle and seasonal cycles such as breeding.
What is the main endocrine function of the hypothalamus?
Coordinates the body’s response to changes in the external or internal environment, to maintain homeostasis.
What is the main function of the Pituitary gland?
Produces a wide range of hormones
Is instructed by both the nervous system (neurochemicals such as dopamine & noradrenaline) and hypothalamus (peptide-hormone messengers) in what is needed.
What is the main function of the Thyroid glands?
Plays an important role in controlling metabolic rate.
produce triiodothyronine (T3) and thyroxine (T4)
What is the main function of the parathyroid glands?
Maintains the appropriate concentration of calcium in the blood.
- Important for strong bones
- Also important role in keeping the heart and nervous system running
What is the main function of the gonads (ovaries/testes)?
To produce the sex steroids.
What is the main function of the Adrenal gland?
Fuels the flight or fight response of stress
- Adrenaline/noradrenaline
- cortisol and aldosterone (manages sodium levels)
What is the main function of the Pancreas?
Controls blood/glucose levels
Insulin decreases glucose levels
Glucagon increases glucose levels
What are the main endocrine ways to influence growth in animals?
Animal growth is influenced by:
- anabolic protein (Growth Hormone)
- steroid (testosterone, oestrogen) hormones
- hormones such as cortisol, which have a catabolic effect at high concentrations.
Which type of cell in the pancreas makes glucagon?
Alpha cells
Which type of cell in the pancreas makes insulin?
Beta cells
