Chapter 13: Coordination and Response: I The nervous System in Mammals

%%Sensitivity%% is the ability to respond to a stimulus (change)

Nervous System of Mammals:

comprises:

• %%Central Nervous System (CNS)%% - brain and spinal cord.
• %%Peripheral Nervous System (PNS)%% - cranial nerves, spinal nerves from spinal cord and sense organs.
• %%Receptors%% are sense organs that receive stimuli.
• %%Effectors%% are muscles.

Neurones:

• %%Sensory neurons%% - transmit impulses from sense organs to CNS.
• %%Relay neurons%% - transmit nerve impulses from sensory neurons to motor neurons - found in CNS.
• %%Motor neurons%% - transmit nerve impulses from CNS to the effector.
• %%Synapse%% is the junction b/w two neurons.

Human Brain:

• %%Forebrain%%

  • @@Cerebrum@@
  • Concerned with intelligence, memory, learning and overall control of voluntary actions.
  • @@Hypothalamus@@
  • Concerned with body temperature and blood osmotic pressure, appetite, sleep and emotions.
  • Produces ADH

• %%Midbrain%%

  • Concerned with visual reflexes e.g movement of eyeball.

• %%Hindbrain%%

  • @@Cerebellum@@
  • Concerned with muscular coordination and maintaining body balance.
  • @@Medulla@@
  • Concerned with involuntary actions such as heartbeat, peristalsis, rate of respiratory movements and contraction.

  

Reflex Actions:

Is an immediate ^^response^^ to a ^^specific stimulus without conscious control.^^

Spinal and Cranial Reflexes:

• ^^spinal^^ - controlled by the spinal cord.
• ^^cranial^^ - controlled by brain.

Reflex Arc

consists of:

1. a receptor or sense organ
2. receptor neuron
3. reflex centre
4. an effector neuron
5. an effector (muscle or gland)

Conditioned Reflex:

Is a ^^reflex action^^ acquired ^^from past experience or learning^^ with a stimulus which is originally ineffective in producing the response.