Human Biology Unit 3

Describe the structure of central nervous system (CNS) and the peripheral nervous system (PNS)

The CNS consists of the brain and the spinal cord.

The PNS consists of the somatic nervous system (SNS) and the automatic nervous system (ANS)

What 2 things does the somatic nervous system contain and describe them

The somatic nervous system contains sensory and motor neurons

Sensory neurons - take impulses from sense organs to the CNS.

Motor neurons - take impulses from the CNS to muscles and glands

What does the autonomic nervous system consist of

The autonomic nervous system (ANS) consists of the sympathetic and parasympathetic systems

Describe the antagonistic actions of the sympathetic and parasympathetic systems on heart rate, breathing rate, peristalsis and intestinal secretions

The sympathetic system speeds up heart rate and breathing rate while slowing down peristalsis and production of intestinal secretions.

The parasympathetic system changes these in a opposite way

Describe the structure and function of converging, diverging and reverberating neutral pathways

In a converging neutral pathway, impulses from several neurons travel to one neuron. This increases the sensitivity to excitatory or inhibitory signals

In a diverging neural pathway, impulses from one neuron travel to several neurons so affecting more than one destination at the same time

In a reverberating pathway, neurons later in the pathway link with earlier neurons, sending the impulse back through the pathway. This allows repeated stimulation of the pathway

What is the cerebral cortex and what does it do

The cerebral cortex is the centre of conscious thought. It also recalls memories and alters behaviour in the light of experience