Unit 3, Aos 1, Dp 2

Question 1

Conscious response

Answer 1

a deliberate and voluntary action that is initiated by the brain
and performed intentionally by the body

Question 2

Conscious response features

Answer 2

● Involves the CNS because the brain is a component of the CNS
● Also involves the somatic NS (division of the PNS)
● Involves awareness
● E.g. you feel cold, so you turn on the heater

Question 3

Conscious response processes

Answer 3

1. Sensory receptors receive information from sense organs
2. Sensory neurons (in the Somatic NS) send information towards the CNS
3. The brain receives and interprets this information and makes a decision on how to move
4. Motor neurons (in the Somatic NS) send this information from the brain towards to effector cells in the skeletal muscles
5. Skeletal muscles move accordingly

Question 4

Unconscious response

Answer 4

• automatic and involuntary action
• performed by the body independently of the brain

Question 5

Unconscious response features

Answer 5

● Occur without conscious awareness in response to internal
and external sensory stimuli
● Often a mechanism for survival i.e. minimise danger
● E.g. you feel cold, you get goose bumps
● The two types of unconscious responses you need to know
are:
○ Physiological responses of the autonomic nervous
system
○ The spinal reflex

Question 6

Sympathetic Responses

Answer 6

• heart rate increases to increase blood flow, enabling high levels of physical activity
• breathing rate increases and lung airways expand to increase oxygenation
• body releases more glucose to energise the body
• bladder relaxes to conserve energy required for physical activity
• pupils dilate, improving vision
• adrenal glands secrete stress hormones, to energise the body

Question 7

Parasympathetic responses

Answer 7

• heart beats at a steady and regular rate that supports optimal and balanced functioning
• pupils constrict
• adrenal glands do not secrete stress hormones, to allow the body to rest
• sweat glands are regulated, controlling perspiration

Question 8

Spinal reflex

Answer 8

• unconscious response to sensory stimuli
• initiated by interneurons in the spinal cord - independently of the brain

Question 9

Steps of Spinal Reflex

Answer 9

1. The sensation of a sensory stimulus is detected by the body’s sensory receptors
2. Sensory signal is sent via afferent neurons to the spinal cord
3. The spinal cord, via interneurons, immediately relays a signal to efferent neurons
4. Motor signal is sent via efferent neurons to initiate an
   automatic/unconscious motor response in the skeletal muscles to the sensory stimulus.
5. Effector cells in the muscles receive the message to withdraw/move
6. As the motor neurons send messages to tell the body to respond unconsciously, sensory neurons send their neural impulses to the brain to make it aware of any pain or sensation.