Endocrine Gland & Homeostasis

Question 1

Endocrine Gland

Answer 1

A gland that secretes a hormone directly into the bloodstream

Question 2

Endocrine Gland

Answer 2

A gland that secretes a hormone directly into the bloodstream

Question 3

Hormone

Answer 3

Protein released in body that travels through blood to target organs where it helps control certain bodily functions

Question 4

Hypothalamus

Answer 4

Part of brain that detects changes within the body & coordinates responses by stimulating release of hormones from organs & glands

Question 5

Pituary gland hormones

Answer 5

Growth hormone
Prolactin
Thyroid stimulating hormone
Corticotropin

Question 6

Acromegaly

Answer 6

Endocrine disorder caused by either abnormal hormone production or abnormal cellular sensitivity & results in bone shaoe changes, broad facial features, enlarged jaw etc

Question 7

Thyroid gland

Answer 7

Gland that requires iodine to function properly & secrete the hormone thyroxine which controls thr basic metabolism rate

Question 8

Cretinism

Answer 8

Severe hypothyroidism after birth leading to stunted physical and mental growth

Question 9

Goitre

Answer 9

Swelling in neck from enlarged thyroid gland due to it nit functioning properly

Question 10

Homeostasis

Answer 10

Maintenance of constant internal environment fluids allowing an organism to be independent from changes in external environment

Question 11

Negative feedback mechanism

Answer 11

Way of regulating the functioning of a system

Question 12

Occurrence of homeostatic control

Answer 12

1. Stimulus
2. Receptor
3. Corrective mechanism
4. Negative feedback

Question 13

Homeostasis in man

Answer 13

Regulation of thyroxine
Thermoregulation
Regulation of blood glucose concentration
Osmoregulation
Regulation of salt
Regulation of CO2

Question 14

Negative feedback when thyroxin is low

Answer 14

1) High levels thyroxin detected by hypothalamus which then secretes a hormone to stimulate PG
2) PG produces more TSH to stimulate production of more thyroxine in thyroid gland
3) increased levels of thyroxine till back to normal thus stopping release of TSH.

Question 15

Salt regulation when low/low blood pressure

Answer 15

Low salt detected & cortex of adrenal glands is stimulated to secrete aldosterone
More sodium ions are reabsorbed in bloodstream from nephrons
Thus increasing salt which increases blood pressure
*Salt levels /blood pressure return to normal. Aldosterone is no longer released

Question 16

Negative feedback during dehydration

Answer 16

Blood has less water stimulating hypothalamus to send impulses to pituitary gland
PG secretes more ADH which travels in blood to kidneys
ADH increases permeability of collecting ducts & distal convulated tubules of kidney
More water re-absorbed & passed to surrounding blood vessels.
Water levels in blood returns tk normal

Question 17

High glucose negative feedback mechanism

Answer 17

Blood gkucose concentration rises above normal level
Islets of Langerhans in pancreas is stimulated to secrete more insulin
Insulin transported to liver & muscles to convert excess glucose to glycogen
Blood glucose concentration decreases & insulin production falls
Blood glucose concentration returns to normal

Question 18

When glucose level in blood decrease

Answer 18

Glucose levels in blood decrease below normal levels stimulating Islets of Langerhans to secrete glucagon
Glucagon travels in blood to liver & muscles that stimulate conversion of stores glycogen to glucose
Glucose level in blood now increases & returns to normal

Question 19

Type 1 diabetes

Answer 19

Little or no insulin produced
Genetic /virus etc
Treated by insulin injections

Question 20

Type 2 diabetes

Answer 20

Insulin produced
Due to lifestyle choices
Treated by tablets to increase glucose uptake & change in lifestyle

Question 21

Structures of the skin

Answer 21

Epidermis
Dermis
Fatty tissue

Nerve
Oil gland
Sweat gland

Question 22

3 layers of skin

Answer 22

Top layer protects against germs & mechanical injury.
Centre layer forms dead skin
Malphihian layer contains melanin which protects against UV rays of sun & replace cells in top 2 layers

Question 23

Vasoconstriction

Answer 23

Process that constricts blood flow ti surface of skin to preserve more heat

Question 24

Vasodilation

Answer 24

Process that increases blood flow to surface of skin to preserve less heat energy

Question 25

Fatty layer

Answer 25

Poor conductor of heat & serves as an indicator

Question 26

How extra heat is gained

Answer 26

Eating hot food
Sun
Warm air
Exercise

Question 27

How heat is lost

Answer 27

Convection
Radiation
Conduction
Evaporation through sweat
Faeces & urine
Exhalation

Question 28

Factors in skin cooling down body’s heat

Answer 28

Evaporation through sweat
Blood vessels near surface radiate heat. Hair kies flat to minimize insulation

Question 29

Regulating body on hot day

Answer 29

Blood & skin temp rise
Temp receptors detect changes & send nerve impulses to brain
Hypothalamus of brain is stimulated to send inpulses to thyroid gland to stop release of TSH
Decreased thyroxine results in a decrease of metabolic rate which decreases heat production
Heat is transferred out of body through sweat etc to cool down & return body temp to normal

Question 30

Low temperature in body negative feedback mechanism

Answer 30

Blood & skin temperature fall. Temp receptors detect changes & send imoulses to stimulate hypothalamus.
Hypothalamus sends impulses to thyroid gland to stimulate release of thyroxine to increase metabolism which increases heat production.
Thus increasing body temp till back to normal

Question 31

High CO2 regulation /low pH

Answer 31

CO2 increase cause receptors in carotid artery to be stimulated
Sends impulse to Medulla oblongata causing Medulla oblongata to beat faster carrying more CO2 to lungs at faster rate & also causing intercostal muscles & diaphragm to contract more to exhale more CO2.
More CO3 exhaled returning levels to normal & increasing pH levels.