Ch. 6 Detecting and Regulating Change

Question 1

Define receptor

Answer 1

A structure that detects stimulus, detect a change in internal/external environment

Question 2

What are the five types of receptors

Answer 2

o	Thermoreceptors
o	Osmoreceptors
o	Chemoreceptors
o	Touch receptors
o	Pain receptors

Question 3

What doe temperature receptors respond to and what are the two types

Answer 3

respond to heat and cold both internally and externally

Peripheral (recptors in skin) and Central (receptors in hypo)

Question 4

Why does the cerebrum be told info from the thermorecpetors

Answer 4

Conscoius aware of temp

Question 5

Where are osmoreceptors located and what are they sensitive to

Answer 5

located in hypothalamus
- Sensitive to osmotic pressure (Which is determined by concentration of substances dissolved in the water of blood plasma)

Question 6

what re chemo receptors stimulated by

Answer 6

chemicals

Question 7

what do chemoreceptors detect in external and internal

Answer 7

• External:
  o E.g. in nose= making sensitive to odours, in mouth= sensitive to tastes
• Internal
  o sensitive to the composition of body fluids

Question 8

whats an important internal chemoreceptor

Answer 8

o In certain blood vessels that are sensitive to pH of blood and to the concentrations of oxygen and carbon dioxide
o These are involved in regulation of the heartbeat and breathing (chap. 8)

Question 9

what are the two types of touch receptors located in skin

Answer 9

1. Occur in greater concentrations in areas of skin more sensitive
   a. e.g. lips, fingertips, eyelids, external genital organs
2. Nerve endings= also associated with base of each hair follicle= respond to light touch that bends hair

Question 10

What are two characteristics of touch receptors

Answer 10

o adapt rapidly, so after short time= no longer aware of touch
o e.g. first putting on clothing= aware of it touching skin, quickly= sensation disappears
o sensitive to very light touches

Question 11

what are pain receptors stimulated by

Answer 11

o damage to tissue
o poor blood flow to a tissue
o excessive stimulation from stimuli such as heat or chemicals

Question 12

where are pain receptors not found

Answer 12

brain

Question 13

do pain receptors adapt and why

Answer 13

• adapt little or not at all // pain continues as long as stimulus is present
• The failure of pain receptors to adapt= awareness a tissue damaging situation exists

Question 14

Define reflex

Answer 14

: A rapid, automatic response to a change in external or internal environment

Question 15

what are the four characteristics of reflexes

Answer 15

1. A stimulus is required to trigger a reflex- the reflex is not spontaneous
2. A reflex is involuntary- occurring without conscious thought
3. A reflex response is rapid- only a small number of neurons are involved
4. A reflex response is stereotyped- it occurs the same way each time it happens

Question 16

what are the four characteristics of reflexes (cheat words)

Answer 16

stimulus
involuntary
rapid
stereotyped

Question 17

define spinal reflex

Answer 17

a reflex carried out by the spinal cord without involvement of the brain (involves three neurons)

Question 18

define reflex arc

Answer 18

in a reflex, the pathway travelled by nerve impulses from receptor to effector (a muscle or gland that carries out a response to a stimulus

Question 19

What are the five components of a reflex arc

Answer 19

1. A receptor is either the ending of a sensory neuron or a specialized cell associated with the end of a sensory neuron. The receptor reacts to a change in internal or external environment by initiating a nerve impulse in the sensory neuron
2. A sensory neuron carries the impulse from the receptor to the CNS
3. There is at least on synapse. The nerve impulse may be passed directly to a motor neuron or there may be one or more interneurons, which direct the impulse to the correct motor neuron
4. A motor neuron carries the nerve impulse to an effector
5. An effector receives the nerve impulse and carries out the appropriate response. Effectors are muscle cells or secretory cells

Question 20

define steady state

Answer 20

dynamic equilibrium in which input and output of materials and energy= balanced

Question 21

Define feedback system

Answer 21

A rapid, automatic response to a change in external or internal environment

Question 22

What are the six features of a steady state model

Answer 22

o The stimulus is the change in the environment that causes the system to operate
o The receptor detects the change
o The modulator is a control center responsible for processing information received from the receptor and for sending information to the effector
o The effector carries out the response counteracting the effector of the stimulus
o Response
o Feedback is achieved because the original stimulus has been changed by the response