Endocrine System

Question 0

Endocrine glands

Answer 0

Secrete hormones into blood vessels that then transport these to target organs

Question 1

Secretions

Answer 1

• A useful substance or fluid produced by cells and released to to the surrounding medium.
• E.g. Sweat, enzymes and hormones

Question 2

Exocrine glands

Answer 2

Glands with ducts to carry secretions to places where they are required

Question 3

The endocrine system

Answer 3

• A system consisting of various endocrine glands releasing hormones
• which act as chemical messengers targeting specific organs

Question 4

Name at least 5 major glands making up the endocrine system

Answer 4

• Hypothalamus
• Pituitary
• Thyroid
• Thymus
• Pancreas
• Adrenal
• Testes
• Ovaries

Question 5

Functions of hormones

Answer 5

• Regulate secretions from endocrine or exocrine glands
• control growth and development of the body
• maintain homeostasis
• regulate metabolism and energy release
• react to stimuli in emergency situations
• control reproduction process

Question 6

When hormones act together for a common effect

Answer 6

Synergistic hormones

Question 7

When hormones act against each other or the effect of one cancels out the effect of the other

Answer 7

Antagonistic hormones

Question 8

Over secretion of hormones

Answer 8

Hyper secretion

Question 9

Under secretion of hormones

Answer 9

Hypo secretion

Question 10

The role of the hypothalamus

Answer 10

• Part of the brain that links the nervous and endocrine systems
• maintains homeostasis
• controls other glands
• particularly involved with pituitary gland function
• produces ADH (secreted by pituitary)

Question 11

The role of the pituitary gland (hypophysis)

Answer 11

• Referred to sometimes as the master gland
• Releases hormones that control metabolic functions and many other endocrine glands

Question 12

Five hormones secreted by pituitary

Answer 12

• Growth hormone GH (growth)
• Thyroid stimulating hormone TSH (thyroid to produce thyroxin)
• Follicle stimulating hormone FSH (ovary or testes function)
• Lutenising hormone LH (ovary or testes function)
• prolactin (mammary gland function)

Question 15

Thyroid gland function

Answer 15

Pituitary gland releases thyroid stimulating hormone (TSH)

Thyroid stimulated to produce thyroxin:

• controls basic metabolic rate of cells
• increases nervous system activity
• increases cardiac output
• affects mental and physical growth and sexuality
• affects alimentary system

Question 16

Hyperthyroidism

Answer 16

Over-secretion of thyroxin

Graves’ disease:

• Increased metabolic rate
• nervousness
• weight loss
• rapid heart rate
• shaky, sweaty and hyperactivity
• goitres causing bulging eyes

Question 17

Hypothyroidism

Answer 17

Under secretion of thyroxin:

cretinism in children:

• low metabolic rate
• retarded growth and mental development,
• thick skin and protruding tongue
• retarded sexual development

myxoedema in adults:

• feel cold,
• gain weight,
• thick skin,
• slow mentally and physically

Question 18

Structure of the pancreas

Answer 18

Exocrine gland (digestive juices) Endocrine gland (islets of Lagerhans): -alpha cells secrete glucagon -beta cells secrete insulin

Question 19

Role of insulin and glucagon

Answer 19

Antagonistic hormones - negative feedback interaction. Hypothalamus detects if blood sugar too high Insulin secretion increased and more glucose converted to glycogen Hypothalamus detects if blood sugar too low Glucagon secretion increased and more glycogen converted to glucose

Question 20

Diabetes

Answer 20

-Not enough insulin produced resulting in elevated blood glucose levels -Extra glucose is excreted by the kidneys -Diabetics need to control intake of carbohydrates and may need daily insulin

Question 21

Type 1 diabetes

Answer 21

Life long condition Pancreas does not produce enough insulin Daily use of insulin required

Question 22

Type-2 diabetes

Answer 22

-Body cells become resistant to insulin or pancreas makes insufficient insulin -Can be triggered by obesity and lack of physical fitness -treatment varies according to the specific nature of the disease e.g. daily insulin

Question 23

The function of anti-diuretic hormone (ADH)

Answer 23

-Regulates water content and body temperature -Osmoreceptors in hypothalamus detect if concentration of solutes in the blood high. -The hypothalamus stimulates the pituitary to release ADH -ADH increases permeability of distal convoluted tubule of the nephron -more water is reabsorbed, less water in urine -a lower concentration of solutes in the blood inhibits secretion of ADH -permeability of the distal convoluted tubules decreases -less water reabsorbed, more water in urine

Question 24

Location of the adrenal glands

Answer 24

One above each kidney

Question 25

Hormones produced by the adrenal glands

Answer 25

Aldosterone Adrenaline

Question 26

Function of aldosterone

Answer 26

Aldosterone targets nephrons in kidney. Increases reabsorption of sodium (salt balance in blood) which also affects water movement by osmosis. Together with ADH it brings about water balance in the body.

Question 27

If the sodium level is too high in the blood...

Answer 27

Less aldosterone secreted Less sodium ions reabsorbed by blood More sodium ions excreted Sodium levels decrease

Question 28

Over secretion of aldosterone results in...

Answer 28

Too much salt in the blood Water retained resulting in odema (swelling) in the tissues

Question 29

Function of adrenaline

Answer 29

Prepares the body to cope with emergency or stress Also known as fight or flight hormone: -increases breathing rate -speeds conversion of glycogen into glucose -accelerates heart rate and blood pressure -increases blood flow to muscles and brain by dilation of vessels -reduces blood flow to digestive system and skin by constriction of vessels -increased metabolism in brain and muscles -increased muscle tone and sweating -stimulates release of cortisone -pupils dilate

Question 30

Hormone produced by testes

Answer 30

Testosterone

Question 31

Hormones produced by ovaries

Answer 31

Oestrogen (from Graafian follicle) Progesterone (from corpus luteum)

Question 32

Function of testosterone

Answer 32

-Development of male secondary characteristics -develops and maintains reproductive organs -sperm production -increased red blood cells at puberty -increased height

Question 33

Function of oestrogen

Answer 33

-Develops and maintains female secondary sexual characteristics -develops and maintains reproductive organs -at puberty increases physical growth

Question 34

Effect of hypo (under) secretion of testosterone

Answer 34

Sterility Addison's disease

Question 35

Effect of hyper (over) secretion of testosterone

Answer 35

Increased masculinity, rate of growth and metabolism Called virilisation

Question 36

Effect of hypo (under) secretion of oestorogen and progesterone

Answer 36

Addison's disease

Question 37

Effect of hyper (over) secretion of oestrogen and progesterone

Answer 37

Irregular ovulation Softening of bones Unusual uterus development

Question 38

Positive feedback mechanisms in the endocrine system

Answer 38

Mechanisms that cause continued or increased secretion.

Question 39

Negative feedback mechanisms in the endocrine system

Answer 39

Mechanisms that make adjustments to bring the body back within an acceptable range. When too high, the gland secreting it reduces secretion and when too low, it increases secretion.

Question 40

Negative feedback of thyroxin levels

Answer 40

-when thyroxin level too low -pituitary is stimulated to secrete more TSH -more TSH causes thyroid gland to secrete more thyroxin -thyroxin levels raised -when thyroxin level too high -pituitary is inhibited from secreting TSH -less TSH causes thyroid gland to secrete less thyroxin -thyroxin levels decreased.

Question 41

Hypo- (under) and hyper- (over) secretion of growth hormone (GH)

Answer 41

Hypo: dwarfism Hyper: giganitism in children, acromegaly in adults

Question 42

Hypo- (under) and hyper- (over) secretion of thyroid stimulating hormone (TSH)

Answer 42

Hypo: cretinism in children, myxoedema in adults Hyper: Grave's disease

Question 43

Hypo- (under) and hyper- (over) secretion of prolactin

Answer 43

Hypo: no milk secretion Hyper: excess milk secretion

Question 44

Hypo- (under) and hyper- (over) secretion of adreno-cortico tropic hormone (ACTH)

Answer 44

Hypo: under-secretion of adrenalin and aldosterone Hyper: over-secretion of adrenaline and aldosterone

Question 45

Hypo- (under) and hyper- (over) secretion of anti-diuretic hormone (ADH)

Answer 45

Hypo: diabetes insipidus Hyper: excessive water retention

Question 46

Usual cause of goitre and cretinism

Answer 46

Lack of iodine in the diet Thyroid gland needs iodine to make thyroxin If there is not enough iodine the thyroid grows larger (goitre) and during pregnancy the foetus may not develop properly

Question 47

chemical coordination

Answer 47

The type of control and coordination brought about by hormones in the blood

Question 48

endocrine glands

Answer 48

ductless glands that release their secretions directly into the bloodstream, which transports them to the target organs

Question 49

exocrine glands

Answer 49

glands that release their secretions via ducts to a body cavity or to the exterior

Question 50

Master gland at the base of the brain, attached by a short stalk to the hypothalamus

Answer 50

hypophysis/pituitary

Question 51

The part of the brain that secretes releasing factors to control the hormone secretions of the hypophysis/pituitary gland

Answer 51

Hypothalamus

Question 52

The hormone, and where it is secreted from, that stimulates the thyroid to secrete the hormone thyroxin

Answer 52

TSH/thyroid-stimulating hormone secreted by the hypophysis/pituitary gland

Question 53

The hormone, and where it is secreted from, that promotes the growth of the skeleton and muscles by stimulating the synthesis of proteins

Answer 53

STH/growth hormone secreted by the hypophysis/pituitary gland

Question 54

Growth disorder in children caused by an under-secretion/hyposecretion of growth hormone

Answer 54

Dwarfism

Question 55

Growth disorder in children caused by an over-secretion/hypersecretion of growth hormone

Answer 55

Gigantism

Question 56

Growth disorder in adults caused by an over-secretion/hypersecretion of growth hormone and the symptoms

Answer 56

Acromegaly Enlarged bones of the face (especially jawbone), hands and feet.