Endocrine system Flashcards
what is homeostasis
The maintenance of a constant internal environment
outline the difference between the exocrine and endocrine gland
Exocrine glands secrete into a duct that carries the secretion to the body surface or to one of the body cavities.
Endocrine glands secrete hormones into the extracellular fluid then usually passes into the capillaries to be transported by the blood
provide definition for a stimulus, receptor, modulator, effector, response and feedback
Stimulus: change in the environment that causes the system to operate.
Receptor: detects the change.
Modulator: control centre responsible for processing information received from the receptor and for sending information to the effector.
Effector: carries out a response counteracting the effect of the stimulus.
Response: is what occurs as a result of the effector.
Feedback: is achieved because the original stimulus has been changed by the response.
what is the difference between positive and negative feedback
POSITIVE Feedback: enhances a response
I.e. Release of oxytocin during child birth
NEGATIVE Feedback: Response opposes the initial response which caused the stimulus
I.e. Returning blood sugar levels to normal after a meal.
list 7 types of receptors
CHEMOreceptors
CHEMICALS
Ions, taste, smell
NOCIceptors
PAIN
Damage to tissues
THERMOreceptors
TEMPERATURE
Skin, hypothalamus
MECHANOreceptors
AKA: Stretch/Baro/Presso
PRESSURE
PHOTOreceptors
LIGHT
Eyes
OSMOreceptors
OSMOTIC PRESSURE
Hypothalamus, kidneys
PROPRIOceptors
TENSION
Muscles, tendons, ligaments
explain how proteins and amines make it to the blood stream vs steroids
proteins and amines
hormones travel in the blood stream until they find the target cell
locks to the receptor on the outside of the cell membrane (the considers first messengers)
target cells then produce substances (second messages)
the second message the alter metabolism and cellular activity
steroids
travels in blood stream until the target cell
penetrates cell membrane and enters target cell
hormones are picked up by receptor molecules in cytoplasm which transports them to nucleus
hormone affects specific dense altering new cellular metabolism / cellular activity by switching genes off and on.
what is the difference between steroid and protein? amine hormones
steroid : are lipid soluble and they do not dissolve in water how they travel
protein and amine: they are water soluble and unable to defuse across the cell membrane so instead they attach to receptor proteins in the membranes od the target cell
list the function and structures of the pineal gland, hypothalamus pituitary gland, thyroid gland parathyroid thymus adrenal gland pancreas ovaries and testis as endocrine glands
pineal gland
Location: Middle of the brain, at the same level as the eyes.
Structure: 1/3 inch (8.3mm), rice-sized, pinecone-shaped, red-grey colour
Function:
Mysterious gland
Produces hormone melatonin
Regulates sleep patterns which in turn affects hormone levels, stress levels and physical performance
hypothalamus
Location/Structure
Directly above the pituitary gland
Function
Regulates: temperature, thirst, hunger, sleep, mood, sex drive, release of other hormones
Hormones
Releasing factors- stimulate hormone release from Pit.
Inhibiting factors- inhibit hormone release from Pit.
pituitary gland: Location/Structure Beneath the hypothalamus Joined by a stalk called ‘infundibulum’ Pea size ~13.5mm diameter Divided into ‘anterior-lobe’ and ‘posterior-lobe’
Function
‘Master Gland’
Regulates the activity of other endocrine glands
Hormone production and release controlled by releasing/inhibiting factors (anterior), or nerves (posterior)
thyroid gland
LOCATION: In the neck, below the larynx
STRUCTURE: Two lobes either side of the trachea, joined by narrow piece of tissue that lies in front of the trachea.
produces thyroxine
parathyroid
LOCATION: 4-6 glands embedded in the rear surface of the thyroid gland lobes. produces parathyroid hormone
thymus
LOCATION: Behind the sternum and between the lungs.
FUNCTION: Is only active until puberty.
After puberty, slowly shrinks and is replaced by fat
THYMOSIN- stimulates the development of disease-fighting T lymphocyte (a type of white blood cell).
adrenal gland
LOCATION: 2 Adrenal glands, one immediately above each kidney.
STRUCTURE: Outer layer (adrenal cortex), inner layer (adrenal medulla)
pancreas
LOCATION: Just below the stomach and along the duodenum, the first part of the small intestine.
STRUCTURE:
Both an exocrine and endocrine gland.
Islets of Langerhans- clusters of endocrine cells: BETA cells and ALPHA cells.
ovaries
produce oestrogen and progesterone
testis
produce testosterone
list are the following hormones are produced, target cells or organs and there effect MELATONIN RELEASING FACTORS INHIBITING FACTORS FOLLICLE STIMULATING HORMONE LUTEINISING HORMONE GROWTH HORMONE THYROID STIMULATING HORMONE ADRENOCORTICOTROPIC HORMONE PROLACTIN ANTIDIURETIC HORMONE OXYTOCIN THYROXINE CALCITONIN PARATHORMONE THYMOSINS ALDOSTERONE CORTISOL ADRENALINE NORADRENALINE INSULIN GLUCAGON TESTOSTERONE (ANDROGENS) OESTROGEN PROGESTERONE
MELATONIN
produced by: Pineal gland
target cell or organ: The central and peripheral nervous system
effect on cell: Regulation of sleep patterns stimulated by release of melatonin darkness and inhibited by light
RELEASING FACTORS
produced by: Hypothalamus
target cell or organ: N/A
effect on cell: stimulate hormone release from Pit.
INHIBITING FACTORS
produced by: Hypothalamus
target cell or organ: N/A
effect on cell: inhibit hormone release from Pit.
FOLLICLE STIMULATING HORMONE
produced by:Pituitary gland Anterior lobe
target cell or organ: Ovaries, and testis
effect on cell: Growth of follicles in the ovaries and spermatogonia and production of sperm
LUTEINISING HORMONE
produced by: Pituitary gland Anterior lobe
target cell or organ: Ovaries and the testis
effect on cell: Ovulation and maintenance of the corpus luteum of the corpus luteum and secretion testosterone
GROWTH HORMONE
produced by: Pituitary gland Anterior lobe
target cell or organ: All cells
effect on cell: Growth and protein synthesis
THYROID STIMULATING HORMONE
produced by: Pituitary gland Anterior lobe
target cell or organ: thyroid gland
effect on cell: Secretion of hormones and thyroid
ADRENOCORTICOTROPIC HORMONE
produced by: Pituitary gland Anterior lobe
target cell or organ: Adrenal cortex
effect on cell: Secretion of hormones from the adrenal cortex
PROLACTIN
produced by: Pituitary gland Anterior lobe
target cell or organ: Mammary glands
effect on cell: Lactogenic hormone which works with other hormones to produce and release breast milk.
ANTIDIURETIC HORMONE
produced by: Posterior lobe
target cell or organ: Kidneys distal proximal tubule and collecting duct
effect on cell: Reabsorption of water from the filtrate into the blood stream.
OXYTOCIN
produced by: Posterior lobe
target cell or organ: Uterus, Mammary glands
effect on cell: Contraction of uterus in childbirth, and mammary glands to release breast milk.
THYROXINE
produced by: Most cells
target cell or organ:Thyroid
effect on cell: Increased metabolic rate and oxygen consumption and heat production
CALCITONIN
produced by: C cells
target cell or organ: Thyroid gland
effect on cell: Calcium regulation
PARATHORMONE
produced by: parathyroid
target cell or organ: Bone
effect on cell: Controls calcium and phosphate levels in the blood
THYMOSINS
produced by: Thymus
target cell or organ: White blood cells
effect on cell: the maturation of T lymphocytes
ALDOSTERONE
produced by: Adrenal cortex
target cell or organ: All body cells
effect on cell: Reduces sodium, increases potassium in the urine.
Kidney reabsorbs sodium ions & water follows > Maintain blood pressure/water concentration
CORTISOL
produced by: Adrenal cortex
target cell or organ: All body cells
effect on cell: Promotes normal metabolism and resistance of the body to stress.
Converts proteins/fats to glucose for energy.
Prepares body to deal with stressors.
Anti-inflammatory effect- depresses immune response.
ADRENALINE
produced by: Adrenal medulla
target cell or organ: N/A
effect on cell: Prepares the body for fight or flight
NORADRENALINE produced by: Adrenal medulla target cell or organ: N/A effect on cell: Increases the rate and force of the heart rate. Flight or fight responses.
INSULIN
produced by: Pancreas
target cell or organ: All cells, liver, skeletal muscles
effect on cell: Reduces the amount of glucose in the blood. Stores glucose as glycogen and fat.
GLUCAGON
produced by: Panaceas
target cell or organ: Liver, Skeletal muscles, adipose tissue
effect on cell: Increases the amount of glucose in the blood by breaking down stores of glycogen and fat.
TESTOSTERONE (ANDROGENS) OESTROGEN
produced by:
target cell or organ:
effect on cell:
TESTOSTERONE (ANDROGENS) produced by: gonads target cell or organ: Most body cell effect on cell: Development and maintenance of male secondary sexual characteristics: deep voice, body hair distribution, growth of skeleton, muscles. Spermatogenesis.
PROGESTERONE
produced by:
target cell or organ:
effect on cell:
how to the posterior lobe of the hypothalamus and the pituitary gland work together and list an example
they are connected via a set of fibres motor neurons these nerves pass through the infundibulotomy a stalk which connects the hypothalamus to the pituitary lives the posterior lobe does not produce hormones it only excrete and secretes hormones the hormones are produced in the hypothalamus and the hormonal travel through the axon and to the axon terminals where the hormone is stored the nerve impulse will trigger the release of the hormone the posterior lobe produces oxytocin and antidiuretic hormone
eg. During childbirth the child puts pressure on the mother’s cervix the brain will send an impulse to the hypothalamus to trigger impose down to the axon terminals to release more oxytocin and the hormone will travel down the bloodstream to the target audience organ and is
- not a true gland because it’s stores and releases hormones which are made in the hypothalamus
how does the hypothalamus and the anterior lobe of the pitutary gland work together
The neuro sensory cells will either secrete and inhibiting or releasing factor into the bloodstream these factors are then released into the blood bloodstream via the system which is a network of what capillaries which take blood directly from the hypothalamus to the anterior lobe inside the anterior lobe of the pituitary gland there is anterior lobe cells or endocrine cells this is where the hormones are produced releasing factors or stimulate the endocrine system to produce a particular hormone whereas inhibiting factors will prevent or stop the endocrine system from producing these hormones the anterior lobe produces six hormones follicle stimulating hormone luteinising hormone human growth thyroid stimulating hormone potassium adreno cortotropic tropic hormone
For example thyroid stimulating hormone is released if metabolism is low the neuro sensory cells will release the viroid stimulating hormone releasing factor secreted into the bloodstream this travels into the anterior lobe until it reaches its target endocrine cell the target enterprise cell will then begin releasing and secreting thyroid-stimulating hormone once released from the target endocrine cells the hormones will be released into the bloodstream and make it to its target organ if there are high levels of metabolism the neurosensory cells will release thyroid stimulating inhibiting factor the inhibiting factor will travel through the hypo seal portal system and then go into the anterior lobe until it reaches the target cell and inhibit the production of thyroid stimulating hormone which means hormone will no longer be released and the levels of thyroxine will decrease
