Functions of the nervous system
- Control: control of homeostasis:
- Movement: Reflexes and voluntary control of movement
- Memory and learning: integration of information
NS Pattern of operation
Detection of environmental stimuli
- Decision making
- actioning of a response
CNS functions
decision making
-integrates info and formulates a response to this info
Control center:
- Controls Muscles, glands
- Controls the endocrine system
- Controls the activity of other organs
PNS
-All the nerves of the body
-Forms a link between the CNS and the organs/tissues
PNS is further subdivided into:
- Afferent Nervous System (sensory)
- Efferent Nervous System (motor)-splits into somatic and autonomic)
Afferent Nervous System
Senses
- Carries information to the CNS
- Made up of nerves and receptors
- These receptors detect any changes in the environment
what are some Internal afferent receptors?
Receptors such as stretch receptors, chemoreceptors, baroreceptors, osmoreceptors
What are some external afferent receptors?
Receptors such as touch receptors, special senses (hearing, sight, smell etc)
Efferent Nervous System
- Motor
- Consists of all the nerves carrying instructions/commands from the CNS to the target (muscle/gland)
- some nerves are both sensory AND motor nerves (vegus). These are called mixed or compound
- Further divided into
◦ Somatic Nervous System
◦ Autonomic Nervous System
Somatic Nervous System
functions
Controls our relationship with the external environment
-Consists of motor nerves that control skeletal muscles
-Action is voluntary i.e. you consciously decide to move
Ex: walking, running, sitting
Autonomic Nervous System: functions
Controls our relationship with the internal environment
-Consists of nerves that carry instructions to the internal organs
-Action is involuntary i.e. AUTOMATIC
Ex: changes in heart rate, gut motility
-Splits into sympathetic and parasympathetic
Parasympathetic
“Rest and digest” controls involuntary functions Ex: Digestion, urination
Sympathetic
“Fight or flight” Prepares the body for immediate physical activity.
Excitable cells of NS
Also known as NEURONS
- Make up 20% of the total cells in the nervous system
- They are the functional cells of the system
- Generate and propagate impulses
Non-excitable
Make up 80% of all cells in the nervous system
- Glial/neuroglial cells found in the CNS
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells
- Schwan and Satellite cells found in the PNS
