Nervous system Physiology notes

Nervous system Physiology notes for MLT students

1. GENERAL PHYSIOLOGY NOTES
UNIT 3
NERVOUS SYSTEM
SUB CODE: BMLT2002
DEPARTMENT OF MEDICAL LAB
TECHNOLOGY
SMAS
FACULTY INCHARGE: Mr. A. VAMSI KUMR (Asst Prof)

2. SYLLABUS
















COURSE OUTCOMES
On completion of this course the students will able to:
1. Demonstrate heart function and circulation of blood in human body
2. Teach Functions of respiratory organs
3. Demonstrate the functions of Nervous system
4. Teach reproductive system & Perform Pregnancy test and explain Fertility
control
5.
Demonstrate the functions of Special sense organs
6.
Demonstrate heart function and circulation of blood in human body

3. SYLLABUS

Unit 1
Cardiovascular System Number of Lecture Hours 8
Heart sounds, Cardiac cycle, ECG, Cardiac output, Heart rate, Arterial pulse, fetal circulation &
Respiration, & Hemorrhage
Pedagogy
tools
Scaleup Lecture

Unit 2
Respiratory system Number of Lecture Hours 5
Pulmonary circulation, Exchange of respiratory gases, Transport of respiratory gases, Regulation
of Respiration & Artificial
respiration
Pedagogy
tools
Scaleup Lecture

Unit
3
Nervous system Number of Lecture Hours 11
Neuron, Classification of nerve fibers, Neuroglia, Receptors, Synapse, Spinal cord, Brainstem,
Thalamus, Internal capsule,
Hypothalamus, Basal Ganglia, Crebellum, EEG, CSF & Epilepsy
Pedagogy
tools
Scaleup Lecture

Unit
4
Reproductive system Number of Lecture Hours 10
Male reproductive system: Seminal vesicles, Prostate gland, Semen. Female Reproductive
system: Ovary, Menstrual cycle, Ovulation, Menopause, Infertility, Pregnancy, Pregnancy tests &
Fertility control
Pedagogy
tools
Scaleup Lecture

Unit
5
Special Senses Number of Lecture Hours 6
sensation of taste, smell, Auditory pathway, Visual pathway, Field of vision & Errors of refraction

Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

4. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Introduction to Nervous System
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

1. INTRODUCTION TO NERVOUS SYSTEM
Introduction:

6. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

7. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Structure of neuron
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

2. STRUCTURE OF NEURON
Introduction:

8. STRUCTURE OF A NEURON:
▪ A typical multipolar neuron consists of three
parts: Dendrites (Dendrons), Cell body (Cyton)
and Axon.
▪ In polarized fibers, the nerve impulse travels
from dendrites to the cyton and from cyton to the
axon.
▪ Cyton or cell body contains groups of ribosomes
and rough endoplasmic reticulum called Nissl
granules.
▪ Such granules are present in the dendrites but
absent in the axon.
▪ The presence of Nissl granules is the
characteristic feature of neurons.
▪ The centrosome is absent in the cyton and
hence the neurons cannot divide.
▪ The cytoplasm and the cell membrane of the
axon are called axoplasm and axolemma
▪ The long fibers of i.e axon or dendrite may
be gray (non-myelinated) or white
(myelinated).
▪ The myelin sheath in PNS is secreted by
Schwann cells. Myelinated nerve fibers are also
called medullated
▪ The covering formed by Schwann cells around
the axon is called Neurilemma.
▪ Due to discontinuous myelin sheath around the
myelinated axon, the fibers are differentiated into
nodes (nodes of Ranvier) and internodes.
▪ At nodes, the myelin sheath is absent but
neurilemma is present.
A typical myelinated multipolar neuron
Ganglion: A ganglion is a group of cytons or cell
bodies. In brain (CNS), such groups are called nuclei.
Nerves: A nerve is mainly the group of axons and in
brain (CNS), such group of axons is called a tract.

9. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

10. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Classification of nerve fibers
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

3. CLASSIFICATION OF NERVE FIBERS
Introduction:
A nerve is an enclosed, cable-like bundle of nerve fibres called axons, in the peripheral nervous system. A
nerve transmit electrical impulses and its the basic unit of the Nervous system. A nerve provides a common
pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of
the axons to peripheral organs or, in the case of sensory nerves, from the periphery back to the central
nervous system. Each axon within the nerve is an extension of an individual neuron, along with other
supportive cells such as Schwann cells that coat the axons in myelin.

11. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

12. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Neuroglia
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

4. NEUROGLIA
Introduction:

13. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

14. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Receptors
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

5. RECEPTORS
Introduction:

16. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

17. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Synapses
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

5. SYNAPSES
Introduction:

19. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

20. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Spinal cord
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

5. SPINAL CORD
Introduction:
The spinal cord is an extension of the brainstem that begins at the foramen magnum and continues down
through the vertebral canal to the first lumbar vertebra (L 1). Here, the spinal cord comes to a tapering point,
the conus medullaris. The spinal cord is held in position at its inferior end by the filum terminale, an
extension of the pia mater that attaches to the coccyx. Along its length, the spinal cord is held within the
vertebral canal by denticulate ligaments, lateral extensions of the pia mater that attach to the dural sheath.
The following are external features of the spinal cord (see Figure 1):
• Spinal nerves emerge in pairs, one from each side of the spinal cord along its length.
• The cervical nerves form a plexus (a complex interwoven network of nerves—nerves converge and
branch).
• The cervical enlargement is a widening in the upper part of the spinal cord (C 4–T 1). Nerves that
extend into the upper limbs originate or terminate here.
• The lumbar enlargement is a widening in the lower part of the spinal cord (T 9–T 12). Nerves that
extend into the lower limbs originate or terminate here.
• The anterior median fissure and the posterior median sulcus are two grooves that run the length of
the spinal cord on its anterior and posterior surfaces, respectively.
• The cauda equina are nerves that attach to the end of the spinal cord and continue to run downward
before turning laterally to other parts of the body.
• There are four plexus groups: cervical, brachial, lumbar, and sacral.The thoracic nerves do not form
a plexus.
figure 1 .External features of the spinal cord.

21. A cross section of the spinal cord reveals the following features, shown in Figure 2:
• Roots are branches of the spinal nerve that connect to the spinal cord. Two major roots form the
following:
• A ventral root (anterior or motor root) is the branch of the nerve that enters the ventral side of the
spinal cord. Ventral roots contain motor nerve axons, transmitting nerve impulses from the spinal
cord to skeletal muscles.
• A dorsal root (posterior or sensory root) is the branch of a nerve that enters the dorsal side of the
spinal cord. Dorsal roots contain sensory nerve fibers, transmitting nerve impulses from peripheral
regions to the spinal cord.
• A dorsal root ganglion is a cluster of cell bodies of a sensory nerve. It is located on the dorsal root.
• Gray matter appears in the center of the spinal cord in the form of the letter H (or a pair of butterfly
wings) when viewed in cross section:
• The gray commissure is the crossbar of the H.
• The anterior (ventral) horns are gray matter areas at the front of each side of the H. Cell bodies of
motor neurons that stimulate skeletal muscles are located here.
• The posterior (dorsal) horns are gray matter areas at the rear of each side of the H. These horns
contain mostly interneurons that synapse with sensory neurons.
• The lateral horns are small projections of gray matter at the sides of H. These horns are present only
in the thoracic and lumbar regions of the spinal cord. They contain cell bodies of motor neurons in
the sympathetic branch of the autonomic nervous system.
• The central canal is a small hole in the center of the H crossbar. It contains CSF and runs the length
of the spinal cord and connects with the fourth ventricle of the brain.
• White columns (funiculi) refer to six areas of the white matter, three on each side of the H. They are
the anterior (ventral) columns, the posterior (dorsal) columns, and the lateral columns.
• Fasciculi are bundles of nerve tracts within white columns containing neurons with common
functions or destinations:
• Ascending (sensory) tracts transmit sensory information from various parts of the body to the brain.
• Descending (motor) tracts transmit nerve impulses from the brain to muscles and glands.
figure 2. A cross section of the spinal cord.

22. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Brainstem
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

6. BRAIN STEM
Introduction:
The brainstem (brain stem) is the distal part of the brain that is made up of the midbrain, pons, and medulla oblongata.
Each of the three components has its own unique structure and function. Together, they help to
regulate breathing, heart rate, blood pressure, and several other important functions. All of these brainstem functions
are enabled because of its unique anatomy; since the brainstem houses cranial nerve nuclei and is a passageway for
many important neural pathways.
MIDBRAIN
The midbrain is the most superior portion of the brainstem. It is located posterior to the hypothalamus and superior to
the pons. It contains reflex centers for head, eye, and body movements in response to visual and auditory stimuli. For
example, reflexively turning the head to enable better vision or better hearing is activated by the midbrain.
PONS
The pons lies between the midbrain and the medulla oblongata and is recognizable by its bulblike anterior portion. It
consists primarily of axons. Longitudinal axons connect lower and higher brain centers, and transverse axons connect
with the cerebellum. The pons also works with the medulla oblongata by controlling the rate and depth of breathing.
MEDULLA OBLONGATA
The medulla oblongata is the most inferior portion of the brain, and it is the connecting link with the spinal cord.
Descending (motor) axons extending between the brain and the spinal cord cross over to the opposite side of the brain
within the medulla oblongata. The medulla oblongata contains three integration centers that are vital for homeostasis:
1. The respiratory rhythmicity center controls the basic rhythm of breathing by triggering each cycle of inhale and
exhale. It is also involved in associated reflexes such as coughing and sneezing.
2. The cardiac control center regulates the rate and force of heart contractions.
3. The vasomotor center regulates blood pressure and blood flow by controlling the diameter of blood vessels.

23. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Thalamus
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

7. THALAMUS
Introduction:
The thalamus is a small structure within the brain located just above the brain stem between the cerebral cortex and
the midbrain and has extensive nerve connections to both. The thalamus is part of the limbic system. The main
function of the thalamus is to relay motor and sensory signals to the cerebral cortex. It also regulates sleep, alertness
and wakefulness.
Location of the thalamus
The brain is comprised of ventricles or fluid-filled spaces. The thalamus surrounds the third ventricle. It is a
subdivision of part of the brain called the diencephalon and is one of the largest structures derived from the
diencephalon during embryonic development.

Functions of Thalamus:
➢ The thalamus is a collection of nuclei that relay information between the cerebral cortex and the periphery,
spinal cord, or brain stem.
➢ All sensory information, except for the sense of smell, passes through the thalamus before processing by the
cortex.
➢ Axons from the peripheral sensory organs, or intermediate nuclei, synapse in the thalamus, and thalamic
neurons project directly to the cerebrum.
➢ It is a requisite synapse in any sensory pathway, except for olfaction.
➢ The thalamus does not just pass the information on, it also processes that information. For example, the
portion of the thalamus that receives visual information will influence what visual stimuli are important, or
what receives attention.

24. ➢ The cerebrum also sends information down to the thalamus, which usually communicates motor commands.
This involves interactions with the cerebellum and other nuclei in the brain stem.
➢ The cerebrum interacts with the basal nuclei, which involves connections with the thalamus.
➢ The primary output of the basal nuclei is to the thalamus, which relays that output to the cerebral cortex.
➢ The cortex also sends information to the thalamus that will then influence the effects of the basal nuclei.
Clinical Significance
As thalamus is an important relay and integrative area, the disease of this region of CNS will have profound effects on
the body. The thalamus may be damaged by neoplasia, disease in arterial supply or due to hemorrhage.

Following are some important clinical significances of thalamus.
Sensory Loss
Lesions of thalamus resulting from hemorrhage or thrombosis of arteries can damage ventral posteromedial and
ventral posterolateral nuclei of thalamus. This can, in turn, lead to the complete sensory loss.
The sensory loss is complete including light touch, tactile, pain, discrimination, and joint and muscle sensations from
the opposite side of the body.
Abnormal Involuntary Movements
The vascular lesions of the thalamus may also lead to choreoathetosis and ataxia. The ataxia may be a result of loss of
appreciation of muscle and joint movements.
Thalamic Hand
The patients with thalamic lesions have a particular abnormal posture of the contralateral hand. In thalamic hand, the
wrist of the person is pronated and flexed, the metacarpophalangeal joints are flexed, and there is an extension at the
interphalangeal joints. The movements of the fingers are also slow.
Thalamic Pain
When a patient is recovering from thalamic infarct, he may experience spontaneous pain. The pain is often excessive
and occurs on the contralateral side of the body.

Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

25. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Internal Capsule
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

7. INTERNAL CAPSULE
Introduction:
The internal capsule describes a region deep in the brain that functions as a communication pathway. The internal
capsule allows communication between areas of the cerebral cortex, and areas of the brainstem. These connections
that are made possible by the pathways of the internal capsule are necessary for physical movement and perception of
sensory information.
The biggest job of the internal capsule is working as a relay station for the body’s motor function. This means that the
internal capsule is necessary for arm, leg, trunk and face movement. The right side of the internal capsule transmits
nerve signals for movement of the left side of the body and the left side of the internal capsule transmits nerve signals
for movement of the right side of the body.
While the internal capsule is primarily involved in movement, it also acts as a relay station for sensation on the
opposite side of the body. The internal capsule is described as ‘white matter’ because of its appearance under a
microscope. The internal capsule is also often referred to as the subcortical area of the brain because it is located
below the cerebral cortex.

Symptoms and Diagnosis
An internal capsule stroke can cause arm weakness, hand weakness, leg weakness or foot weakness, described as
hemiparesis or hemiplegia. You might have some strength left in the affected area (hemiparesis,) or you might not be
able to move it at all (hemiplegia.) An internal capsule stroke may affect the face, making it difficult to chew, swallow
or speak clearly.

26. The internal capsule is a pathway connecting nerves that control your sensation as well as your motor function, an
internal capsule stroke can cause you to lose some or all sensation in the affected arm, leg or face.
Because so many important pathways run through the internal capsule, a relatively small internal capsule stroke can
cause severe weakness or sensory loss.
If you have had an internal capsule stroke, it can usually be visualized on brain MRI or brain CT scan within a short
time after the stroke. However, because internal capsule strokes are small, sometimes they are not clearly apparent in
brain imaging studies, even when they cause profound symptoms

Reference:
https://www.verywellhealth.com/internal-capsule-stroke-3146452

27. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Hypothalamus
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

8. HYPOTHALAMUS
Introduction:
The hypothalamus is a small but important area in the center of the brain. It plays an important role in
hormone production and helps to stimulate many important processes in the body and is located in the brain,
between the pituitary gland and thalamus.
When the hypothalamus is not working properly, it can cause problems in the body that lead to a wide range
of rare disorders. Maintaining hypothalamic health is vital because of this.

Function
The hypothalamus is a small but essential part of the brain.
The hypothalamus' main role is to keep the body in homeostasis as much as possible.
Homeostasis means a healthful, balanced bodily state. The body is always trying to achieve this balance.
Feelings of hunger, for example, are the brain's way of letting its owner know that they need more nutrients
to achieve homeostasis.
The hypothalamus acts as the connector between the endocrine and nervous systems to achieve this. It plays
a part in many essential functions of the body such as:

28. • body temperature
• thirst
• appetite and weight control
• emotions
• sleep cycles
• sex drive
• childbirth
• blood pressure and heart rate
• production of digestive juices
• balancing bodily fluids
As different systems and parts of the body send signals to the brain, they alert the hypothalamus to any
unbalanced factors that need addressing. The hypothalamus then responds by releasing the right hormones
into the bloodstream to balance the body.
One example of this is the remarkable ability of a human being to maintain an internal temperature of 98.6
°Fahrenheit (ºF).
If the hypothalamus receives a signal that the internal temperature is too high, it will tell the body to sweat.
If it receives the signal that the temperature is too cold, the body will create its own heat by shivering.
Hormones of the hypothalamus
To maintain homeostasis, the hypothalamus is responsible for creating or controlling many hormones in the
body. The hypothalamus works with the pituitary gland, which makes and sends other important hormones
around the body.
Together, the hypothalamus and pituitary gland control many of the glands that produce hormones of the
body, called the endocrine system. This includes the adrenal cortex, gonads, and thyroid.
Hormones secreted by the hypothalamus include:
1. antidiuretic hormone, which increases how much water is absorbed into the blood by the kidneys
2. corticotropin-releasing hormone, which helps regulate metabolism and immune response by working with
the pituitary gland and adrenal gland to release certain steroids
3. gonadotropin-releasing hormone, which instructs the pituitary gland to release more hormones that keep
the sexual organs working
4. oxytocin, a hormone involved in several processes, including the release of a mother's breast milk,
moderating body temperature, and regulating sleep cycles
5. prolactin-controlling hormones, which tell the pituitary gland to either start or stop breast milk production
in lactating mothers
6. thyrotropin-releasing hormone activates the thyroid, which releases the hormones that regulate
metabolism, energy levels, and developmental growth

29. The hypothalamus also directly influences growth hormones. It commands the pituitary gland to either
increase or decrease their presence in the body, which is essential for both growing children and fully
developed adults.

Disorders
A hypothalamic disease is any disorder that prevents the hypothalamus from functioning correctly. These
diseases are very hard to pinpoint and diagnose because the hypothalamus has a wide range of roles in the
endocrine system.
The hypothalamus also serves the vital purpose of signaling that the pituitary gland should release hormones
to the rest of the endocrine system. As it is difficult for doctors to diagnose a specific, incorrectly
functioning gland, these disorders are often called hypothalamic-pituitary disorders.
In these cases, there are some hormone tests that doctors might prescribe to get to the root of the disorder.
Causes and risk factors
The most common causes of hypothalamic diseases are injuries to the head that impact the hypothalamus.
Surgeries, radiation, and tumors can also cause disease in the hypothalamus.
Some hypothalamic diseases have a genetic link to hypothalamic disease. For instance, Kallman syndrome
causes hypothalamic problems in children, most noticeably delayed or absent puberty, accompanied by an
impaired sense of smell.

30. Hypothalamus problems also appear to have a genetic link in Prader-Willi Syndrome. This is a condition in
which a missing chromosome leads to short stature and hypothalamic dysfunction.
Additional causes of hypothalamic disease can include:
• eating disorders, such as bulimia or anorexia
• genetic disorders that cause excess iron buildup in the body
• malnutrition
• infections
• excessive bleeding
Symptoms of hypothalamus disorders
Symptoms of hypothalamus disorders vary depending on what hormones are in short supply.
Children might show signs of abnormal growth and abnormal puberty. Adults might show symptoms linked
to the various hormones their bodies cannot produce.
There is usually a traceable link between the absent hormones and the symptoms they produce in the
body. Tumor symptoms might include blurred vision, loss of vision, and headaches.
Low adrenal function might produce symptoms such as weakness and dizziness.
Symptoms caused by an overactive thyroid gland include:
• sensitivity to heat
• anxiety
• feeling irritable
• mood swings
• tiredness and difficulty sleeping
• lack of sex drive
• diarrhea
• constant thirst
• itchiness

Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs
4. Understanding Medical Physiology by RL Bijlani

31. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Basal Ganglia
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

8. BASAL GANGLIA
Introduction:
The basal ganglia or basal nuclei are clumps of gray mass located below the cortex in the depth of both cerebral
hemispheres. These nuclei can have different shapes and are involved in the control of movement.
The basal ganglia are surrounded by a white mass of the cerebral hemisphere, and the individual nuclei that enter into
their composition build the walls of the lateral cerebral chambers.

The most prominent functions of the basal ganglia include:
• One of the major roles of the basal ganglia is to participate in the control of complex patterns of motor
activity such as: letter writing, cutting paper with scissors, throwing a ball into a basket, adding the ball in
football, many aspects of vocalization, controlled eye movements, or literally all our other skilled
movements.
• Cognitive control of motor activity in which the nucleus caudatus plays a major role is another important
function of the basal ganglia. Likewise, planning which movement patterns will be used together, or in what
order in order to achieve a complex goal, is another role of the basal ganglia.
Other functions include:
Represents the accessory motor system. Mediates between neocortical motor centers and the “elderly” motor areas
of the brainstem Selects the purposeful and desired motor activity and suppresses unwanted movements.
• Acts by modifying ongoing neural activity in motor projections
• Delivers an inhibitory role in motor control
• Inhibits muscle tone (balance of excitatory and inbound input signals according to PMN terminating on
skeletal muscle)
• Monitor and adjust slow and continuous contractions (equilibrium, body position, etc.)
• Regulates attention and individual cognitive processes
• Participates in motor planning and learning
• Assisting the cerebral cortex in making subconscious, learned movements
• Temporal pattern of movement and gradation of the intensity of movement

32. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Cerebellum
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

8. CEREBELLUM
Introduction:
The cerebellum (which is Latin for “little brain”) is a major structure of the hindbrain that is located near the
brainstem.1This part of the brain is responsible for a number of functions including motor skills such as balance,
coordination, and posture.
Location of the Cerebellum
The cerebellum is the largest structure of the hindbrain and can be found in the back portion of the skull below the
temporal and occipital lobes and behind the brainstem.
When looking at the brain, the cerebellum looks much like a smaller structure separate from the brain, found beneath
the hemispheres of the cerebral cortex. The cerebellum consists of a cortex covering white matter, as well as a
ventricle filled with fluid. It is also divided into two hemispheres like the cerebral cortex.

Functions of cerebellum:
The cerebellum is the area at the back and bottom of the brain, behind the brainstem. The cerebellum has several
functions relating to movement and coordination, including:
1. Maintaining balance: The cerebellum has special sensors that detect shifts in balance and movement. It
sends signals for the body to adjust and move.
2. Coordinating movement: Most body movements require the coordination of multiple muscle groups. The
cerebellum times muscle actions so that the body can move smoothly.
3. Vision: The cerebellum coordinates eye movements.

33. 4. Motor learning: The cerebellum helps the body to learn movements that require practice and fine-tuning. For
example, the cerebellum plays a role in learning to ride a bicycle or play a musical instrument.
5. Other functions: Researchers believe the cerebellum has some role in thinking, including processing
language and mood. However, findings on these functions are yet to receive full exploration.
Disorders
As a result of the close relationship between the cerebellum and movement, the most common signs of a cerebellar
disorder involve a disturbance in muscle control.
Symptoms or signs include:
• lack of muscle control and coordination
• difficulties with walking and mobility
• slurred speech or difficulty speaking
• abnormal eye movements
• headaches
There are many disorders of the cerebellum, including:
• stroke
• brain bleeds
• toxins
• genetic anomalies
• infection
• cancer
Ataxia
The main symptom of cerebellum dysfunction is ataxia.
Ataxia is a loss of muscle coordination and control. An underlying problem with the cerebellum, such as a virus or
brain tumor, can cause these symptoms.
Loss of coordination is often the first sign of ataxia, and speech difficulties follow soon after.
Other symptoms include:
• blurry vision
• difficulty swallowing
• tiredness
• difficulties with precise muscle control
• changes in mood or thinking
Several factors can cause ataxia, including:

34. • genes
• poisons that brain damage
• stroke
• tumors
• head injury
• multiple sclerosis
• cerebral palsy
• chicken pox and other viral infections
Sometimes ataxia is reversible when the underlying cause is treatable. In other cases, ataxia resolves without
treatment.
Ataxia disorders
Share on Pinterest Ataxia can severely impact mobility.
Ataxia disorders are degenerative conditions. They can be either genetic or sporadic.
A genetic mutation causes genetic or hereditary ataxia. There are several different mutations and types.
These disorders are rare and even the most common type, Friedreich's ataxia, affects only 1 in 40,000 people.
The doctor will diagnose Friedreich's ataxia after ruling out a range of other causes. Genetic testing can identify the
condition, which usually appears in childhood.

35. Sporadic ataxia is a group of degenerative movement disorders for which there is no evidence of inheritance. This
condition usually progresses slowly and can develop into multiple system atrophy.
It presents a range of symptoms, including:
• fainting
• problems with heart rate
• erectile dysfunction
• loss of bladder control
These disorders usually get worse over time. There is no specific treatment to soothe or resolve symptoms, except in
cases of ataxia where the cause is a vitamin-E deficiency.
There are several devices that can help people with irreversible ataxia, such as canes and specialized computers to
support mobility, speech, and precise muscle control.
Ataxia caused by toxins
The cerebellum is vulnerable to poisons, including alcohol and certain prescription medications.
These poisons damage nerve cells in the cerebellum, leading to ataxia.
The following toxins might cause ataxia:
• alcohol
• drugs, especially barbiturates and benzodiazepines
• heavy metals, including mercury and lead
• solvents, such as paint thinners
Treatment and expected recovery time depend on the toxin involved and the extent of brain damage.
Viral ataxia
A virus can cause ataxia.
This disorder is called acute cerebellar ataxia, and it is most commonly occurs in children. Ataxia is a rare
complication of the chicken pox virus.
Other viruses associated with acute cerebellar ataxia are Coxsackie virus, Epstein-Barr, and HIV. Lyme disease, a
bacterial infection, might also cause the condition.
There is no treatment for viral ataxia. It usually resolves in a few months, once the viral infection goes away.
Ataxia caused by stroke
Stroke is a clot or bleed in any part of the brain. The cerebellum is a less common site for stroke than the cerebrum,
but it can still occur there.

36. A clot or bleed in the cerebellum can cause the following:
• ataxia
• headache
• dizziness
• nausea
• vomiting
Treating the stroke might resolve the ataxia. Occupational and physical therapy can help manage any permanent
damage.


Reference:
medicalnewstoday.com/articles/313265.php#disorders

37. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Electroencephalogram (EEG)
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

9. ELECTROENCEPHALOGRAM (EEG)
Introduction:

38. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs

39. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Cerebrospinal fluid (CSF)
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

10. CEREBROSPINAL FLUID (CSF)
Introduction:

42. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs

43. Course Name/ code General Physiology – II / BMLT2002
Unit/ Module/ CO 3
Area & Topic Cerebrospinal fluid (CSF)
Faculty In charge Mr. A. Vamsi Kumar (Asst Prof)
Department / School Medical lab technology, SMAS
Semester II

10. CEREBROSPINAL FLUID (CSF)
Introduction:

44. Reference:
1. Text book of Medical Physiology by Sembulingam & Prema Sembulingam
2. Text of Anatomy & Physiology by Ross & Willson
3. Review on Medical Physiology by Ganogs