Week 3: The Central and Peripheral Nervous System

Question 1

What is the central nervous system?

Answer 1

• composed of the brain and spinal cord (connects brain with peripheral nervous system)

Question 2

What is the role of the spinal cord?

Answer 2

• extension of the brain
• protected by bone and fluid
• cord links the rest of the body to the brain by transmitting messages between the brain and the peripheral nervous system
• the spinal cord can work independently from the brain in order to protect us from injury e.g. reflex from pain

Question 3

What are the four key parts of the brainstem and their functions?

Answer 3

1. Medulla: controls involuntary impulse
   - controls heartbeat, coughing, swallowing, breathing, blood pressure
2. The Pons “the bridge”: Voluntary Movement
   - connect to left and right halves of the cerebellum
   - influences body movement
   - influences sleep and dreaming
3. The Midbrain: Sensory information and motor control
   - processes sensory information
4. Reticular Formation: Prevents sensory overload
   - located at the core of the brainstem
   - regulates / directs stimuli
   - plays role in arousal and attention
   - filters sensory input to prevent sensory overload

Question 4

What are the key parts of the brain?

Answer 4

1. The Cerebellum:
   - orchestrates the movements necessary to perform every day activities without conscious effort (walking, eating)
2. Thalamus: relay station for senses flowing between upper and lower brain
   - directs information flowing in and out of higher centres of the brain
3. Hypothalamus: Master Regulator
   - most influential part of the brain
   - regulates hunger, thirst, sexual arousal, emotional behaviours, biological clock (wakefulness) and physiological changes in the body accompanied by strong emotions
   - maintains all bodily functions except blood pressure, breathing and heartbeat

Question 5

What is the limbic system and what role does it have in the brain?

Answer 5

Group of structures deep within the brain that are collectively involved in emotional expression, memory and motivation
- Amygdala: plays important role in emotion; learning of fear responses that help humans avoid dangerous situations; damage to amygdala impairs one’s ability to recognize tone of voice and facial expressions
- Hippocampus: plays central role in longterm memory; place of cell regeneration, plays role in brain mapping

Question 6

What is the peripheral nervous system?

Answer 6

Made up of nerves that connect the central nervous system with the rest of the body.

Question 7

What are the two subdivisions of the peripheral nervous system and what are their roles?

Answer 7

1. Somatic Nervous System (external regulation)
   - consists of sensory nerves which transmits information from the sense receptor to the central nervous system
   - makes it possible for us to sense our environment
   - is primarily under conscious control
2. Autonomic Nervous System (internal)
   - under unconscious control
   - transmits messages from the central nervous system to the glands, heart, smooth muscles

a) Sympathetic nervous system (fight for flight)
b) Parasympathetic nervous system (brings body back to normal state by conserving body’s energy)