Regulation and disruption

Question 1

Homeostasis

Answer 1

the maintenance of a constant, optimal internal environment despite changes in the external environment

Question 2

Homeostatic mechanisms

Answer 2

controlled by the nervous and endocrine system; the nervous system sends electrical impulses, endocrine system secretes hormones to counteract the stimulus

Question 3

Negative Feedback Loop

Answer 3

The response reduces or eliminates the stimulus causing the effect
Eg. Dropping body temperature

Question 4

Positive Feedback Loop

Answer 4

The response intensifies the stimulus

Question 5

Dynamic Equilibrium

Answer 5

Fluctuations around the set point, controlled by homeostasis

Question 6

Set Point

Answer 6

The optimum level around which levels fluctuate

Question 7

Location of thermoreceptors

Answer 7

Thermoreceptors are found within the skin and mucous membrane (peripheral thermoreceptors) and in the hypothalamus and vital organs (central thermoreceptors)

Question 8

Function of peripheral thermoreceptors

Answer 8

provide info about the external environment: cold and hot receptors

Question 9

Function of central thermoreceptors

Answer 9

detect changes in internal temperatures

Question 10

Heat Exhaustion

Answer 10

Caused by dehydration and continuous vasodilation, causing low blood pressure.
Person may collapse, but internal body temperature remains normal

Question 11

Heat Stroke

Answer 11

Caused by high temperatures and humidity – body temperature increases past 42˚C.
Causes regulatory mechanisms to cease

Question 12

Hypothermia

Answer 12

Core temperature falling below 33˚C; causes metabolic rate to slow, decreased heat production

Question 13

Heat Transfer

Answer 13

Conduction, radiation, evaporation, convection

Question 14

Intracellular fluid

Answer 14

found inside the cells

Question 15

Extracellular fluid

Answer 15

outside the cells, including blood plasma

Question 16

Intercellular Fluid

Answer 16

between cells (interstitial fluid)

Question 17

Plasma

Answer 17

fluid within the blood stream

Question 18

Lymph

Answer 18

any fluid found within the lymph vessels

Question 19

Lyphedema

Answer 19

Lymphatic obstruction causing excess extracellular fluid to collect outside the lymph vessels

Question 20

Dehydration

Answer 20

Water loss exceeds water intake through vomiting, sweating, or diarrhoea
Severe thirst, low blood pressure, dizziness, headache

Question 21

Water Intoxification

Answer 21

Dilation of bodily fluids, leading to cells taking in more water by osmosis

Question 22

Effect of Alcohol on Water Regulation

Answer 22

Inhibits ADH production – decreased water reabsorption in the collecting duct

Question 23

Insulin

Answer 23

produced by the beta cells in the pancreas, and decreases blood glucose levels

Question 24

Ways Insulin lowers BGL

Answer 24

Accelerates the transport of glucose from blood to cells, conversion of glucose to glycogen, stimulates conversion of glucose into adipose tissue, increase in protein synthesis

Question 25

Glucagon

Answer 25

produced in the alpha cells in the pancreas, and increases blood glucose levels

Question 26

Ways glucagon increases BGL

Answer 26

Stimulates glycogenolysis

Question 27

Adrenaline and Cortisol (Blood Sugar regulation)

Answer 27

Stimulates glycogenolysis | Stimulates gluconeogenesis

Question 28

Glycogenesis

Answer 28

Glucose to glycogen

Question 29

Glycogenolysis

Answer 29

Glycogen to glucose

Question 30

Gluconeogenesis

Answer 30

Conversion of non-glucose sources into glycogen (deamination)

Question 31

Ions that regulate gas concentrations

Answer 31

Concentration of oxygen, carbon dioxide and hydrogen ions (pH) regulate breathing

Question 32

Regulation of oxygen

Answer 32

Extremely low concentrations of oxygen are detected by the aortic and carotid bodies, as well as the medulla; these send a nerve impulse to the respiratory centre in the medulla, which then stimulates the intercostals and diaphragm to contract

Question 33

Regulation of carbon dioxide

Answer 33

A relatively small increase in carbon dioxide concentration can stimulate an increase in breathing rate and depth An increase in CO2 concentrations leads to an increase in hydrogen ion concentration This is detected by peripheral and central chemoreceptors; medulla is most sensitive to CO2 changes

Question 34

Regulation of hydrogen ions

Answer 34

As hydrogen ions increase, blood pH decreases | Decrease in pH is detected by the peripheral chemoreceptors

Question 35

Breathing structures

Answer 35

To increase breathing rate, both the intercostal muscles and the diaphragm are stimulated to contract via the intercostal nerve and the phrenic nerve respectively

Question 36

Danger of hyperventilation before diving

Answer 36

Reduced levels of CO2 in the blood stream prior to diving means the urge to breath won’t be triggered at the right time. Decreased O2 levels mean the person will blackout whilst underwater, causing them to inhale whilst under the water

Question 37

Diabetes

Answer 37

Blood sugar levels are regulated by insulin and glucagon; either doesn’t secrete enough insulin, or cells are resistant to the effects of insulin

Question 38

Type 1 Diabetes

Answer 38

Insulin dependent/ juvenile diabetes Autoimmune disease – leucocytes attack beta cells Insulin is injected

Question 39

Type 2 Diabetes

Answer 39

Adult onset / non-insulin dependent Insulin in produced, but the cells don’t respond to it – lifestyle disease - Lack of physical disease

Question 40

Lifestyle factors contributing to type 2 diabetes

Answer 40

Lack of physical exercise, overweight / obese, diet high in fat, sugar and salt, low in fibre, high blood pressure, high blood cholesterol, smoking

Question 41

Hyperthyroidism (Grave's Disease)

Answer 41

Excessive thyroxine Genetic predisposition; rapid heart rate, weight loss, increased appetite, fatigue, sweating, anxiety, protruding eyeballs

Question 42

Treatment of hyperthyroidism

Answer 42

Drugs blocking thyroid’s use of iodine Surgery Radioactive Iodine

Question 43

Hypothyrodism

Answer 43

Too little thyroxine, can be caused by iodine deficiency Thyroid may enlarge, causing a goitre Slow heart rate, weight gain, fatigue, intolerance to cold, swelling of the face Pregnant women with an iodine deficiency can give birth to mentally and physically handicapped babies (cretinism)

Question 44

Hashimoto's Disease

Answer 44

Autoimmune disease - leucocytes attack thyroid cells

Question 45

Treatment of hypothyroidism

Answer 45

Either supplementation with iodine, thyroid hormone replacement therapy