NERVOUS AND ENDOCRINE

Question 1

What are the 3 main functions of nervous system

Answer 1

1. sensory input - monitoring stimuli
2. integration - interpreting sensory input
3. motor output - response to stimuli via effector organs

Question 2

basic steps of nervous system

Answer 2

1. sensory input
2. integration
3. motor output

Question 3

Two sections of nervous system

Answer 3

1. Central Nervous Sytem = brain and spinal cord
2. Peripheral nervous system =
   - paired spinal and cranial nerves (messages to and from spinal cord and brain)

Question 4

first divisions of peripheral system

Answer 4

1. Sensory (afferent) division
   - somatic afferent nerves carry impulses from skin, skeletal muscles and joints to the brain
   - visceral afferent fibres - transmit impulses from visceral organs to the brain
2. Motor (efferent) division
   - impulses from CNS to effector organs, muscles and glands

Question 5

divisions of Motor division

Answer 5

1. somatic (voluntary)
   - conscious control of skeletal muscles
   - somatic motor nerve fibres conduct impulse from CNS to skeletal muscles
2. Autonomic (involuntary)
   - regulates smooth muscle, cardiac muscle, glands

Question 6

divisions of autonomic (involuntary) motor division

Answer 6

1. sympathetic - fight or flight
2. parasympathetic - rest and digest
   *antagonisitic, keep us in a state of dynamic balance

Question 7

what are Somatic reflexes

Answer 7

• fast, involuntary sequence of acions in response to stimulus
• inborn
• involves skeletal muscle

Question 8

what are vibrissae

Answer 8

• an organ of touch
• hair follicle suspended in expanded sinus of fluid - maximise response to hair movement (whiskers)

Question 9

label the eye

Answer 9

• eyelid
• sclera
• conjunctiva
• iris
• pupil
  -retina
• cornea
• lens

Question 10

difference between monocular and binocular vision

Answer 10

monocular - see separate scenes with eye
- detect predators
- can’t judge height and distance

Binocular - one scene in both eyes
- best for judging distance
- best for hunted

Question 11

what are the chemical sense

Answer 11

• taste
• smell
• flehmen

Question 12

explain taste

Answer 12

• tongue has chemoreceptors (taste buds)
• excited by food molecules dissolved in saliva
• mostly found on tongue in papillae (bumps)

Question 13

explain smell

Answer 13

• olfaction receptors excited by airbone chemicals that dissolve in fluids coating nasal membranes
• organ of smell = 5cm squared patch olfactory epithelium on roof of nasal cavity

Question 14

what is the flehmen

Answer 14

curling of the lips allows odorant chemicals into vomeronasal organ - detects pheromones for breeding

Question 15

how does hearing work

Answer 15

sound through ear canal. eardrum vibrates, ossicles amplify and deliver vibrations to cochlear = receptor organ

Question 16

how do organisms balance

Answer 16

• equilbrium receptors in ear = vestibular aparatus - measures gravity with cilia of hair cells in semi-circular canals

Question 17

series of homeostasis

Answer 17

1. stimuli
2. receptor - detect stimuli
3. integrating centre - assess input, initiates response
4. effector - corrects stimuli

Question 18

Types of control systems of homeostasis

Answer 18

1. Autoregulation - cells, tissue, organs change automatically in response to signals inside e.g. blood supply to active muscles
2. Extrinsic conrol by nervoous and endorcrine systems - changes stimulated by signals from outside body

Question 19

define nervous and endocrine control

Answer 19

nervous - brain and spinal cord signals cause change; rapid but short term

endocrine - glands produce hormones cause changes; response is slower but long effects (making chemicals and travelling to target cells)

Question 20

types of chemical communication

Answer 20

• direct via gap junctions
• chemical messengers (endocrine)

Question 21

what are gap junctions - simplest form of chemical communication

Answer 21

• link adjacent cells
• connexons form channels to link cytosol of cells

Question 22

Explain 6 chemical messenger classifications

Answer 22

1. classic endocrine - diffuse to distant cell (usually via bloodstreams) e.g. growth hormones
2. Paracrine - diffuse to nearby target cell e.g. histamine
3. Autocrines - bind to receptors on the secretory cell e.g growth factors
4. cytokines - either act locally, diffuse to nearby cell or diffuse to far cell * interferons*
5. neurotransmitters - secreted from neurons at axon terminal, binds to target cell (synaptic signalling), e.g. ACh to contract skeletal muscle
6. Neurohormones - hormones secreted by neurons, diffuse in bloodstream to far target cell. e.eg ADH from pituitary gland.

Question 23

How do nervous and endocrine system work in the face of stress

Answer 23

• CNS sends nerve signal through soinal cords to adrenal gland where adrenaline is produced in response by adrenal medulla.
• Hypothalamus releases hormones which stimulates pituitary gland to release ACTH. hormone to adrenal cortex, releases cortisol

Question 24

Neg vs pos feedback and examples

Answer 24

Neg: reverse stimulus/disturbance to homeostasis e.g. blood pressure increase, baroreceptors send info to brain, brain signals heart to contract more slowly to decreased pressure, blood pressure decreased

Pos: reinforces stimulus. e.g. cut causes clotting by palates, palates relese chemical to attract more palates, increases clotting

Question 25

what is homeorhesis

Answer 25

coordinated control of metabolism for homeostasis