homeostasis

Question 1

homeostasis D

Answer 1

maintenance of a relatively constant internal environment via negative feedback mechanisms to restore optimal norm levels

Question 2

hormones definition

Answer 2

chemical substances produced by a gland, carried by the blood, which alters the activity of one or more specific target organs and is destroyed by the liver

Question 3

endocrine glands

Answer 3

ductless, hormones are secreted directly into bloodstream

Question 4

exocrine glands

Answer 4

produce and secrete subs. via ducts

Question 5

islet of Langerhans (cells)

Answer 5

(endocrine)
produce and secrete insulin and glucagon directly into the bloodstream

Question 6

pancreatic duct

Answer 6

secretes digestive enzymes and bicarbonate (from exocrine glands) which leads to duodenum

Question 7

type 1 diabetes mellitus

Answer 7

insufficient production of insulin
early onset, insulin injections

Question 8

type 2

Answer 8

insulin resistance
late onset, medication, healthy diet & lifestyle

Question 9

diabetes effect

Answer 9

body is unable to maintain its blood glucose concentration within norm

Question 10

iris F

Answer 10

-pigment
-antagonistic muscles (circular and radial) control amount of light entering the eye

Question 11

pupil F

Answer 11

allows light to enter the eye

Question 12

cornea F

Answer 12

refracts light ray towards pupil

Question 13

lens F

Answer 13

refract and focus light on retina

Question 14

ciliary muscles F

Answer 14

contraction and relaxation alter thickness and curvature of lens
contraction: thicker, more convex
relaxation: thinner, less convex

Question 15

choroid F

Answer 15

1. blood vessels - provide oxy & gluc to retina, remove metabolic waste
2. pigmented black - absorb light, prevent internal reflection of light in eye

Question 16

retina F

Answer 16

has photoreceptors that generates nerve impulses

Question 17

optic nerves

Answer 17

transmits nerve impulses

Question 18

how do we see?

Answer 18

-light rays refracted by cornea and lens
-stimulates photoreceptors on retina
-nerve impulses generated, transmitted along sensory neurones in optic nerves to brain
(brain interprets nerve impulses to see object)

Question 19

reflex action (eg. of involuntary)

Answer 19

immediate response to specific stimulus without conscious control

Question 20

voluntary action

Answer 20

deliberate action with conscious control (starts from the brain)

Question 21

spinal reflex

Answer 21

spinal cord is reflex centre of reflex action

Question 22

cranial reflex

Answer 22

brain is reflex centre of reflex action