PY1101 Lecture Notes - Lecture 3: Somatic Nervous System, Parasympathetic Nervous System, Sympathetic Nervous System
14 Jun 2018
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Lecture 3
Biological Basis of Behaviour
The nervous system
- Interactive network of nerve cells called neurons
- Uses both electrical and chemical means to send the receive messages
- Enables communication between all parts of the body
The peripheral nervous system PNS tea
- Composed peripheral nerves that lie outside the CNS
- The somatic nervous system: controls voluntary movements
o Includes sensory neurons that carry sensory signals from the skin, muscles,
joints, eyes etc. to the central nervous
o Somatic motor neurons that project to a skeletal muscles and carry motor
signals from the central nervous system
o Responsible for carrying motor and sensory information both to and from the
brain, body wall and extremities to the central nervous system
- The autonomic nervous system: controls involuntary responses
o Participates in the regulation of internal environment
o Composed of nerves that carry sensory information from the internal organs
to CNS and nerves which carry motor signals from the CNS to the internal
organs
o Responsible for regulating key involuntary functions of the body including the
activity of the heart, muscle and various bodily functions
o Consists of two spatially segregated subdivisions
o Are integrated and work together but in many ways they create directly
opposite reactions in the body
▪ Sympathetic nervous system (fight or flight)
• Participates in the response of the body to stress
• Stimulates, organises, and mobilises energy resources for fight
or flight
• Stops digestion, directions more blood to muscles, increases
heart rate, dilates pupils
▪ Parasympathetic nervous system (rest and digest)
• Ats to osee the odys esoues ad estoe euiliiu
to resting state
• Resumes control when an emergency has passed
• Supports activities that maintai the odys stoe of eegy
• Also involved in regulating heart rate and pupil size
Central nervous system CNS oah
- CNS of adult can be divided into seven anatomical regions
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o Spinal cord, medulla, pons, cerebellum, midbrain, diencephalon, cerebral
hemispheres
- Composed of brain and spinal cord
- Brain: receives and processes information, initiates responses, stores memories,
generates thoughts and emotions
- Spinal cord: conducts signals to and from the brain, controls reflex activities
Spinal Cord
- Extends from base of skull through the first lumbar vertebra, i.e does not run the
entire length of the spinal column
- Receives sensory info. From skin, joints, and muscles of trunk and limbs and also
contains the motor neurons responsible for both voluntary and reflex movements
- Also receives sensory info from internal organs and has clusters of neurons that
control many visceral functions
Three of next four divisions of CNS (medulla, pons, midbrain) form a continuous structure
termed the brain stem
- Brain stem located rostral to spinal cord
o Receives sensory info. From skin and joints in head, neck, and face and
contains the motor neurons that control the muscles to head and neck
o Also concerned with specialised senses such as hearing taste and balance
o Many visceral functions such as regulation of heart rate. Respiration and
blood pressure take place within the medulla
o If destroyed, death results
- Cerebellum
o Lies dorsal to pons and medulla and bulges out toward the back of the head,
wrapping around the brain stem
o Has pleated surface and is divided into several lobes, each with its own
function
o Receives sensory input from the spinal cord, motor info. From the cerebral
cortex and input about balance from the vestibular organs of the inner ear
o Convergence of all this input enables the cerebellum to co-ordinate the
planning, timing and patterning of skeletal muscle during movement
o Also plays a role in maintaining posture and co-ordinating head and eye
movements
- Midbrain
o Smallest brain stem component
o Several regions play a dominant role in the direct control of eye movements
whereas others are involved in motor control of skeptal muscles
- Diencephalon / hypothalamus
o Lies ventral to thalamus and regulates autonomic nervous system and
secretion of hormones by pituitary gland
o Hypothalamic nuclie are critically involved in the regulation of emotion,
hunger, thirst, body temperature and sexual function, specialises in the
control of the internal organs and the ANS and the endocrine system
- Thalamus
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Document Summary
Uses both electrical and chemical means to send the receive messages. Enables communication between all parts of the body. Composed peripheral nerves that lie outside the cns. The somatic nervous system: controls voluntary movements. Cns of adult can be divided into seven anatomical regions: spinal cord, medulla, pons, cerebellum, midbrain, diencephalon, cerebral hemispheres. Brain: receives and processes information, initiates responses, stores memories, generates thoughts and emotions. Spinal cord: conducts signals to and from the brain, controls reflex activities. Extends from base of skull through the first lumbar vertebra, i. e does not run the entire length of the spinal column. From skin, joints, and muscles of trunk and limbs and also contains the motor neurons responsible for both voluntary and reflex movements. Also receives sensory info from internal organs and has clusters of neurons that control many visceral functions. Three of next four divisions of cns (medulla, pons, midbrain) form a continuous structure termed the brain stem.
