Human Systems

Question 0

Exotherms

Answer 0

Gain or lose heat from the external environment

Question 1

Homeostasis

Answer 1

The maintenance of a constant internal environment in an organism

Question 2

Endotherms

Answer 2

Generate their own heat from metabolic reactions

Question 3

Role of excretory system in homeostasis?

Answer 3

• regulates body temp.
• controls osmosis (salt and water conc.)
• controls concentration of body fluids
• removes waste products of metabolism from the body

Question 4

Give the precise location of the kidneys?

Answer 4

Just below the diaphragm in the small of the back

Question 5

Sensory neurons

Answer 5

Takes messages from the sense organs

to the cns

Question 6

Motor neurons

Answer 6

Take messages from the cns to the effectors causing them to respond

Question 7

Interneurons

Answer 7

Are found in the cns and take messages between sensory and motor neurons

Question 8

Receptor

Answer 8

Is a cell/tissue that detects a stimulus

Question 9

Dendrites

Answer 9

Are fibres that carry impulses toward the cell body

Question 10

Axons

Answer 10

Carry impulses away from the cell body

Question 11

Schwann cells

Answer 11

Are located along the length of neurons. They make the myelin sheath

Question 12

The myelin sheath

Answer 12

Is a fat-rich membrane that insulated electrical impulses

Question 13

The cell body

Answer 13

Has a nucleus and organelles. It forms dendrites, axons and neurotransmitter chemicals

Question 14

A ganglion

Answer 14

Is a group of cell bodies located outside the cns

Question 15

Neurotransmitter chemicals

Answer 15

Carry impulses from one nerve cell to another

Question 16

A neuron

Answer 16

Is a nerve cell

Question 17

A synapse

Answer 17

Is a region where two neurons come into close contact

Question 18

A synaptic cleft

Answer 18

Is the tiny gap between two neurons at a synapse

Question 19

The threshold

Answer 19

The minimum stimulus needed to cause an impulse to be carried

Question 20

The ‘all or nothing law’

Answer 20

States that if a threshold is reached then an impulse is carried, but if a threshold is not reached no impulse is carried

Question 21

The refractory period

Answer 21

Is a short timespan after a neuron has carried an impulse during which a stimulus fails to cause a response

Question 22

The speed at which an electrical impulse is carried depends on….

Answer 22

• the presence or absence of the myelin sheath

- the diameter of the dendrite or axon (larger diameter faster)

Question 23

A reflex action

Answer 23

An automatic, involuntary response to a stimulus

Question 24

A reflex arc

Answer 24

Is made up of the neurons forming the pathway taken by nerve impulses. The functional unto of the nervous system

Question 25

Glands

Answer 25

Are structures that secrete substances

Question 26

Exocrine glands

Answer 26

Release their products into ducts or tubes e.g salivary glands and gastric glands

Question 27

An endocrine gland

Answer 27

Is a ductless gland that produces hormones that are released directly into the bloodstream

Question 28

Why do endocrine glands need a rich blood supply?

Answer 28

Because they secrete hormones into tissue fluid then pass into the bloodstream

Question 29

A hormone

Answer 29

Is a chemical messenger produced by an endocrine gland and carried by the bloodstream to another part of the body where it has a specific effect

Question 30

Growth Hormone (GH)

Answer 30

Produced in the pituitary gland. Causes cells to absorb amino acids and form proteins which causes growth. In particular it causes elongation of the bones of the skeleton

Question 31

The hypothalamus secretes hormones that...

Answer 31

Control the pituitary in response to messages from the brain (i.e links endocrine and nervous system). Also produces anti-diuretic hormone ADH, which controls osmoregulation in the kidneys

Question 32

The thyroid gland

Answer 32

Produces thyroxine which controls all metabolism

Question 33

The pancreas exocrine function?

Answer 33

Islets of Lamgerhans produce insulin. Causes cells to absorb glucose from blood for respiration

Question 34

What is meant by feedback in relation to hormone action?

Answer 34

When the level of a hormone in the blood controls the production of another hormone/ more of itself

Question 35

Plasma proteins

Answer 35

Antibodies and clotting proteins

Question 36

Role of plasma

Answer 36

Transport dissolved materials e.g glucose, amino acids, hormones

Question 37

Role of erythrocytes

Answer 37

Transport oxygen

Question 38

Role of leukocytes

Answer 38

Defend and fight against infection

Question 39

Phagocytes

Answer 39

White blood cells that digest bacteria

Question 40

Role of thrombocytes

Answer 40

Clot blood. Reduces loss of blood and prevents entry of microorganisms

Question 41

How is a clot produced?

Answer 41

When damaged body cells produce chemicals that stimulate platelets to form a clot

Question 42

Role of lymphocytes

Answer 42

To make antibodies

Question 43

Open circulatory system

Answer 43

Heart pumps blood into open-ended vessels. Blood leaves vessels + flows around all cells e.g insects

Question 44

Closed circulatory system

Answer 44

Blood remains in continuous system of blood vessels. Materials are exchanged between the blood and cells thought the thin walls of the smallest blood vessels

Question 45

Difference between veins and arteries

Answer 45

Veins have thinner middle layer (involuntary muscle) therefore a larger lumen

Question 46

Function of collagen in blood vessels...

Answer 46

Prevents walls from over-expansion

Question 47

Blood pressure

Answer 47

The force blood exerts against the wall of a blood vessel

Question 48

Valves

Answer 48

Control the direction of blood flow

Question 49

Give the precise location if the heart

Answer 49

Between the two lungs slightly to the left hand side of the thorax and just above the diaphragm

Question 50

Pulmonary circuit

Answer 50

Heart ➡️ Lungs ➡️ Heart

Question 51

Systemic Circuit

Answer 51

Heart ➡️ Body ➡️ Heart

Question 52

A portal system

Answer 52

Is a blood pathway that begins and ends with capillaries e.g hepatic portal vein connects stomach and intestines to the liver

Question 53

Pacemaker

Answer 53

A small bundle of specialised tissue that controls heartbeat

Question 54

Diastole

Answer 54

Her heart chambers relax

Question 55

Systole

Answer 55

When the heart chambers contract

Question 56

A pulse

Answer 56

Is the alternate expansion and contraction of the arteries

Question 57

Human dental formula

Answer 57

2( i 2/2, c1/1, pm 2/2, m 3/3)

Question 58

The function of the lymphatic system

Answer 58

Forms a link between different parts of blood