APP 6 Flashcards
What is the endocrine system made up of? (2)
Clusters of epithelial cells that secrete hormones (messenger molecules)
What is the endocrine system for, and how does it do what it does? (3)
To maintain homeostasis - the messenger molecules make cells do things that keep conditions in the body relatively constant when things around are changing
Why are the glands of the endocrine system called ductless glands? (3)
because they don’t release their hormones into ducts – they are secreted into the tissues and enter the blood vessels
Why don’t all cells respond to all hormones? (1)
Because only certain cells have receptors for certain hormones
What happens when hormones reach the target tissue cells? (1)
They change what those cells are doing
What are the 2 ways by which hormones can change what a cell is doing?
Fat soluble hormones switch on the gene(s) in the DNA that contain the ‘instructions’ for the ‘job’
Water soluble hormones bind to a receptor and act as enzymes that make the cell do its job
Which other system, besides the endocrine system, maintains homeostasis? (1)
Nervous system (esp ANS)
What are the differences between the way the nervous and endocrine systems work? (6)
Neurotransmitters act very locally, and act very quickly for a very short time
Hormones act over a wide area, work more slowly, and last for a long time
What 3 types of stimulus can make glands secrete hormones? (3)
Nervous signals
Chemical changes in blood
Other hormones
How is the secretion of most hormones controlled, and what is the one exception to this? (2)
Negative feedback, oxytosin
Which two major systems does the hypothalamus control? (2)
NS and endocrine system
What do most of the hormones released by the hypothalamus do? (1)
Make the pituitary glands release their hormones
How do the hormones secreted by the hypothalamus get to the anterior pituitary? (1)
Via hypophyseal portal system
How do secretions of the hypothalamus get to the posterior pituitary? (1)
Neurones that start in the hypothalamus reach down into the posterior pituitary and release neurotransmitters, NOT hormones, which are stored there
Which two hormones are released from the posterior pituitary? (2)
ADH and Oxytosin
What is the stimulus that causes human growth hormone to be released from the anterior pituitary gland? (1)
Low blood sugar
What effect does too much human growth hormone have on children and adults? (2)
Giantism and acromegaly
What effect does too little growth hormone have on children?(1)
Pituitary Dwarfism (Lorain-Levi Syndrome)
Where is the thyroid gland? (1)
Around the larynx
Which two hormones does the thyroid gland release? (2)
T3 is triiodothyromine (has 3 Iodine atoms)
T4 is thyroxine (has 4 iodine atoms)
What is the main effect of T3 and T4 on body cells
Allows them to access more oxygen so they can produce more energy (inc BMR)
List 5 symptoms of hyperthyroidism (5)
Increased heart rate, Fatigue, Weight loss, Heat intolerance, Xs sweating, Hyperactive reflexes, Tremor exophthalmos, Nervousness, Polydipsia (thirst), Increased appetite, Shortage of breath, Swollen neck (enlargement of thyroid gland - goitre), Bulging eyes, (eyelids retract and eye muscles inflamed – exopthalmos)
What is the main hormone secreted by the testes and what does it do? (3)
Testosterone
Regulates sperm production,
Stimulates production and maintenance of male characteristics eg beard growth, deepening of the voice
What are the two main hormones produced by the ovaries? (2)
Oestrogen, progesterone
What are the 4 main things the female sex hormones do? (4)
Regulate the menstrual cycle
Maintain pregnancy
Prepare mammary glands for lactation
Establish and maintain the female body shape
What does prolactin do in women? (1)
Prolactin initiates and maintains milk production by the mammary glands
Where do the glucocorticoid hormones come from, and what is their overall effect? (3)
Adrenal cortex
Mobilising energy, responding to stress
What causes Cushing Syndrome ? (1)
Oversecretion of glucocorticoids
What is the main effect of Melanin Stimulating Hormone o skin? (3)
It causes specialised skin cells called melanocytes to produce the pigment melanin which protects cell DNA from UV light damage
What are the 2 main hormones released by the posterior pituitary? (2)
ADH, oxytosin
What are the 2 main things oxytosin does? (2)
Increases smooth muscle contraction in uterus to eject baby
Stimulates breasts to promote milk ejection
(ejection + production = lactation)
What does Anti Diuretic Hormone do? (2)
Causes the kidneys to retain more water and decrease urine volume
Reduces sweating and constricts small arteries, raising blood pressure (hence alternative name, ‘vasopressin’
What effects does reduced ADH have? (3)
Reduced ADH causes the kidneys to reabsorb less water, leading to:
xs dilute urine
dehydration
extreme thirst (polydipsia)
Where are the ‘hormones’ adrenaline and noradrenaline manufactured (‘trick’ question)? (1)
Hypothalamus
Under what circumstances are adrenal medulla hormones (adrenaline & noradrenaline) released, and which part of the nervous system are they associated with? (2)
Stress, sympathetic
From which cells is calcitonin released, and where are these cells located?(2)
Parafollicular, thyroid
How does calcitonin reduce blood calcium? (1)
Reduces activity of osteoclasts
Where are the 4 parathyroid glands? (1)
In the thyroid gland
How does parathyroid hormone increase blood calcium? (1)
It increases the number and activity of osteoclasts
Where are the 4 parathyroid glands? (1)
In the thyroid gland
Where would you find beta cells, what do they secrete, and what is the effect? (3)
Beta cells secrete insulin which reduces blood glucose
Where would you find alpha cells, what do they secrete, and what is the effect? (3)
Alpha cells secrete glucagon which increases blood glucose
Very briefly, what’s the difference between Type1 and Type 2 diabetes? (2)
Type 1, absence or shortage of insulin
Type 2, cells resistant to insulin because of lifestyle factors
What is the main mineralocorticoid hormone secreted by the adrenal cortex, and what are the 3 main things it helps regulate? (4)
Aldosterone, blood pressure, blood volume, acidity,
Where is the pineal gland, what does it release, and what effect does it have? (3)
Roof of the 3rd ventricle.
Releases Melatonin and regulates sleepiness
What do the kidneys do? (4)
Filter the harmful waste products from the blood to form urine which is then excreted from the body.
At the same time, the concentrations of important molecules in the blood, including water, are adjusted to meet the current needs of the body
Which 2 hormones do the kidneys release? (2)
Erythropoietin and calcitrol
(calcitrol involved in calcium homeostasis and bone density - released from the kidney via stimulation from parathyroid glands)
Where does the urea and ammonia excreted from the kidneys come from? (1)
Break down of amino acids (from proteins)
Where does the bilirubin in urea come from? (1)
Breakdown of haemoglobin in RBC’s
Where does the uric acid in urea come from? (1)
Breakdown of DNA & RNA
Which artery and vein supply the kidneys? (1)
Renal
What are the 3 stages of urine formation? (3)
Glomerular filtration, tubular reabsorption, tubular secretion
What is the ‘functional unit’ of the kidney ? (1)
Nephron
Which part of the nervous system is the detrusor muscle connected to? (1)
Autonomic
What is the urethra? (1)
A small tube leading from the bladder to the outside
Through which gland does the ureter pass in the male? (1)
Postate
Which part(s) of the nervous system are the internal urethral sphincter and external urethral sphincter connected? (2)
Autonomic and somatic respectively
What is micturition? (1)
Another word for urination
What is the inability to control micturition called? (1)
Incontinence
What’s the difference between asexual and sexual reproduction and what’s the advantage of sexual? (3)
Sexual = splitting in two, asexual = combining characteristics of 2 parents, advantage = mix give variation which may suit changed environment better
Where are the sperm produced? (1)
Testes
What is the purpose of the scrotum? (1)
To keep the sperm cool
What’s the really ‘different’ thing that happens in spermatogenesis? (1)
The chromosomes are reduced from 23 pairs to 23 singles
What do the chromosomes contain? (1)
The DNA (packaged up as genes)
How long may sperm last in the female reproductive tract? (1)
48 hours
Why do sperm cells have a lot of mitochondria? (1)
They need a lot of energy to do a lot of movement
Which cells secrete the hormone testosterone? (1)
Leydig cells
Which 2 hormones together stimulate sperm production in the testes? (2)
Testosterone and FSH
Where does fertilisation usually occur? (1)
Fallopian tubes
Where should the fertilised egg implant and develop? (1)
Uterus
What is the endometrium and what does it do? (2)
Mucus membrane that feeds the developing embryo
What are the mammary glands? (2)
Modified sweat glands that produce milk
What is oogenesis? (1)
How one cell in the ovary develops into an egg
Which 4 hormones are released from the Graafian follicle (later, corpus luteum? (4)
Progesterone, oestrogen, relaxin, inhibin
Approximately how many eggs mature and ovulate in a lifetime? (1)
About 400
