Human Physiology of Nerves system

1. Physiology of Nervous System
Prep: Amen Ullah BS Surgical Technology
KMU-IPMS

2. Course Outlines
• Introduction to nerve system
• Classification of neurons
• The Limbic System
• Physiology of different parts of the brain
Date 2, Feb 2018

3. DIVISIONS OF NERVOUS SYSTEM
• Primarily, nervous system is divided
into two parts:
1. Central nervous system
2. Peripheral nervous system.

4. Parts of brain

5. Organization of nervous system

6. Introduction to nerve system
• The nervous system is the system which receives information from
inside and outside the body, integrates it and transmits impulses from
brain and spinal cord to various parts of the body functions and co-
ordinates between body and brain.
• The nervous system coordinates all body functions, enabling a person
to adapt to changes in internal and external environment
• The nervous system is composed mainly of the nerve cells (neurons)
and supporting cells (neuroglia)

7. The Neuron
• Neuron or nerve cell is defined as the structural and functional unit of
nervous system.
• This is the basic conducting cell of the nervous system
• Highly specialized but cannot reproduce itself
• Main parts are the cell body (soma), the fibers: axon and dendrites.

8. The Neuron
• The axon is a long process with myelin sheath. This conducts impulses
away from the cell body
• The dendrites are short, thick, diffuse branching processes that
receive impulses and conduct them towards the cell body

9. The Neuron
• Neurons are classified by three different methods.
A. Depending upon the number of poles
B. Depending upon the function
C. Depending upon the length of axon.

10. CLASSIFICATION OF NEURONS
A. Depending upon the number of poles
1. Unipolar neurons
2. Bipolar neurons
3. Multipolar neurons.
B. Depending upon the function
1. Motor or efferent neurons
2. Sensory or afferent neurons
C. Depending upon the length of axon
1. Golgi type I neurons
2. Golgi type II neurons.

11. Classification of nerve fibers
• 1. Depending Upon Structure
i. Myelinated Nerve Fibers
ii. Non-myelinated Nerve Fibers
2. Depending Upon Distribution
i. Somatic Nerve Fibers
ii. Visceral or Autonomic Nerve Fibers
3. Depending Upon Origin
i. Cranial Nerve Fibers
ii. Spinal Nerve Fibers
„4. Depending Upon Function
i. Sensory Nerve Fibers
ii. Motor Nerve Fibers
5. Depending Upon Secretion Of Neurotransmitter
i. Adrenergic Nerve Fibers
ii. Cholinergic Nerve Fibers

12. Conti…
6. Depending Upon Diameter And Conduction Of Impulse
i. Type A nerve fibers
Type A nerve fibers are divided into four types:
a. Type A alpha or Type I nerve fibers
b. Type A beta or Type II nerve fibers
c. Type A gamma nerve fibers
d. Type A delta or Type III nerve fibers.
ii. Type B nerve fibers
iii. Type C nerve fibers

13. The Neuroglia
• The supporting cells
• They supply nutrients to the neurons and help maintain the electrical
potential
• Neuroglial cells are non-excitable and do not transmit nerve impulse
(action potential). So, These cells are also called non-neural cells or
glial cells.

14. Brain (physiology)
The Cerebrum
• This is the largest part of the brain
• Consists of right and left hemisphere connected by the corpus
callosum
• Each cerebral hemisphere is composed of four different lobes- frontal,
temporal, parietal and occipital
• Embedded in the cerebrum is the Basal ganglia

15. The Frontal Lobe of the cerebrum
• Influences the personality of the person
• Also responsible for judgment, abstract reasoning, social behavior,
language expression and motor movement.

16. The Temporal lobe of the Cerebrum
• This part of the cerebrum controls the hearing, language
comprehension, storage and recall of memories
• The Limbic system is deeply located in the temporal lobe. This
controls the basic drives such as hunger, anger, emotion and sexual
drive.

17. The Parietal lobe of the cerebrum
• This is the principal center for the reception and interpretation of
Sensation
• This part interprets and integrates the sensory inputs like touch,
temperature and pain
• It interprets size, shape, distance and texture

18. The Occipital lobe of the cerebrum
• This functions mainly to interpret visual stimuli.
• Correctly understand what your eyes are seeing
• If our occipital lobe was impaired, or injured we would not be able to
correctly process visual signals

19. Speech areas in the Cerebrum
• Wernicke’s area- responsible for the sensory reception of speech.
• Broca’s Area- responsible for the motor speech

20. The Limbic System
• The Limbic System is a complex set of structures found just beneath
the cerebrum and on both sides of the thalamus.
• It combines higher mental functions, and primitive emotion, into one
system. It is often referred to as the emotional nervous system. It is
not only responsible for our emotional lives, but also our higher
mental functions, such as learning and formation of memories.
• The Limbic system explains why some things seem so pleasurable to
us, such as eating and why some medical conditions are caused by
mental stress, such as high blood pressure.

21. The Diencephalon (Thalamus & Hypothalamus)
• Thalamus:
It serves as a relay station for impulses traveling to and
from the spinal cord, brain stem, cerebellum and cerebrum. It has an
important function in directing sensory input to the appropriate place
in the cerebral cortex. Sensory input from the body, the eyes, ears and
other senses (except for smell) pass through the thalamus.

22. The Diencephalon (Thalamus & Hypothalamus)
• Hypothalamus:
It is an important center for many critical internal body functions.
The hypothalamus monitors water concentration, hormone
concentrations and body temperature. It is associated with feelings of
rage, aggression, hunger and thirst.
It also plays an important role as an intermediary between the
nervous system and the endocrine system (hormones). The
hypothalamus has many connections with the pituitary gland and can
produce and regulate hormones.

23. The Midbrain
• This connects with the Cerebrum.
• Contains numerous ascending & descending tracts and fibers
• The midbrain helps to relay information for vision and hearing.

24. The Hindbrain (Cerebellum, Pons & Medulla Oblongata)
Cerebellum:
• It is the second largest region of brain
• It also has two hemispheres
• Functions to maintain muscle tone, coordinate muscle movement,
posture and control balance/equilibrium
• If this region got damaged; muscle tone decreases and fine motor
movements become very clumsy

25. The Pons
• Connects the cerebellum with the cerebrum
• Houses the respiratory center and cardiovascular center
• Exit points for cranial nerves 5, 6 and 7

26. The Medulla Oblongata
• The most inferior portion of the brainstem
• Serves as the center for autonomic reflexes to maintain homeostasis,
regulating respiratory vasomotor and cardiac functions
• Serves as exit of cranial nerves 9,10,11 and 12

27. Thank You