Bpharma 2nd sem notes Anatomy

1. UNIT -1
THE NERVOUS SYSTEM
By-
Ms. Aishwarya Gangwar
MMCP, Ambala

2. OVERVIEW OF THE NERVOUS
SYSTEM
🞇The nervous
system has two
major anatomical
subdivisions;
🞇The central
nervous system
(CNS)
🞇The peripheral
nervous system
(PNS)

3. SUBDIVISION OF THE NERVOUS SYSTEM

4. CELLS OF THE NERVOUS SYSTEM
🞇There are two cells of the nervous
system. These are;
Neuron
Neuroglia
🞇The functional unit of the nervous
system is the nerve cell, or neuron
🞇Neuroglia or glial are supportive cells in
the nervous system that aid the function
of neurons

5. NEURONS (Nerve Cells)
🞇Neurons have three fundamental
physiological properties:
1. Excitability
2. Conductivity
3. Secretion
🞇A typical neuron is divided into three
parts;
 Soma or cell body (perikaryon)
 Dendrites
 Axon

6. STRUCTURE OF A NEURON

7. CLASSIFICATION OF NEURONS
🞇Neurons may be classified according
to structure or function.
Function
neuron
• Interneuron
(association)
• Motor neuron
Structure
• Sensory (afferent)• Unipolar neurons
• Bipolar neurons
• Multipolar
neurons
• Anaxonic neurons

8. FUNCTIONAL CLASSIFICATION

9. STRUCTURAL CLASSIFICATION

10. NEUROGLIA (Glia)
🞇There are six types of supportive cells
🞇Four occur in the CNS
 Oligodendrocytes
 Ependymal cells
 Microglia
 Astrocytes
🞇Two occur in the PNS
 Schwann cells (Neurilemmocytes)
 Satellite cells

11. TYPES OF NEUROGLIA

12. SYNAPTIC TRANSMISSION
🞇The meeting point between a neuron
and any other cell is called a synapse
🞇The synapses b/t neurons and skeletal
muscle cells are referred to as
myoneural or neuromuscular
junction
🞇Synapse can be;
Chemical synapse
Electrical synapse

13. ANATOMY OF A SYNAPSE

14. CENTRAL NERVOUS SYSTEM
🞇The CNS consists of the brain
and spinal cord
🞇CNS protected by a cranium
surrounding the brain
🞇vertebral column surrounding
the spinal cord
🞇The CNS is bathed in
cerebrospinal fluid
🞇The CNS is composed of gray
and white matter

15. THE BRAIN
🞇 The brain is semi-spherical but soft delicate
complex organ.
🞇It is the center for control and integration
🞇An adult brain weighs near 1.5 kg (3-3.5lbs)
🞇Averages about 1,600 g (3.5 lb) in men
🞇1,450 g in women
🞇Composed of an estimated 100 billion (1011)
neurons
🞇 Anatomically, the brain is divided into 3 region;
🞇Forebrain
🞇Midbrain
🞇Hindbrain

16. DIVISIONS OF THE BRAIN

18. 🞇The brain is lined by membrane
called meninges.
🞇 The brain is conspicuously marked
by surface gyri (folds) and sulci
(grooves).
🞇The human brain is composed of
neurons, glial cells and blood
vessels.
🞇It also consists of four internal,
interconnected chambers called
ventricles.

19. SURFACE ANATOMY OF THE BRAIN

20. FOREBRAIN
🞇 Forebrain consist of the following regions; Telecephalon
(cerebrum) and Diencephalon (Thalamus, hypothalamus,
epithalamus and pituitary gland)
 CEREBRUM
🞇 The cerebrum is the largest part of the brain.
🞇 It is divided into two hemispheres separated by the
longitudinal fissure.
🞇 The hemispheres are prominently marked with gyri and
sulci.
🞇 Portions of the two hemispheres are connected internally
by the corpus callosum
🞇 Each cerebral hemisphere is subdivided by deep sulci, or
fissures, into the five lobes: Frontal, Parietal, Occipital,
Temporal and Insula

21. ANATOMY OF THE CEREBRUM

22. LOBES OF THE CEREBRUM

23. DIENCEPHALON
🞇 A major autonomic region of the brain that consists of vital
structures such as;
🞇 Thalamus, Hypothalamus , Epithalamus , Pituitary
gland
🞇 completely surrounded by the cerebral hemisphere of the
telencephalon.
🞇 These structures surround the third ventricle of the brain
🞇 The thalamus is a large ovoid mass of gray matter
🞇 The hypothalamus is a small portion of the diencephalon
inferior to the thalamus
🞇 The epithalamus is the dorsal portion of the diencephalon
that includes a thin roof over the third ventricle.
🞇 The pituitary gland, or hypophysis, is positioned on the
inferior aspect of the diencephalon

25. MIDBRAIN
🞇The midbrain is a short section of the
brain stem between the diencephalon
and the pons
🞇A short segment of the brainstem that
connects the hindbrain and forebrain
🞇Within the midbrain is the cerebral
aqueduct (aqueduct of Sylvius)
🞇It includes important centers for
vision, hearing, pain, and motor
control

26. ANATOMY OF THE MIDBRAIN

27. HINDBRAIN
🞇 The embryonic hindbrain differentiates into two
subdivisions the metencephalon and
myelencephalon
🞇 The metencephalon is the most superior portion
of the hindbrain.
🞇The pons which measures about 2.5 cm long,
forms a broad anterior bulge in the brainstem
just rostral to the medulla.
🞇It conducts signals up and down the brainstem
and between the brainstem and cerebellum
🞇 The cerebellum is the largest part of the
hindbrain and receives most of its input by way
of the pons.
🞇 Occupies the inferior and posterior aspect of
the cranial cavity

28. ANATOMY OF HINDBRAIN

29. MYELENCEPHALON
🞇Myelencephalon
contain the
medulla oblongata
🞇The medulla
oblongata is a
bulbous structure
about 3 cm (1In)
long
🞇Externally, the
medulla resembles
the spinal cord

30. MENINGES OF THE
CENTRAL NERVOUS SYSTEM
🞇The CNS is protected by
three connective tissue
membranes coverings
called meninges
🞇From superficial to deep ,
they are;
🞇Dura mater,
🞇Arachnoid mater,
🞇Pia mater

31. CEREBROSPINAL FLUID &
VENTRICLES OF THE BRAIN
 ventricles
Two lateral ventricles
A third and fourth ventricles
🞇The brain has four internal chamber called
🞇The fourth ventricle is located in the brain
stem
🞇The cerebral aqueduct (aqueduct of
Sylvius) passes through the midbrain to
link the third and fourth ventricles.
🞇 CSF is a clear fluid that forms a protective
cushion around and within the CNS

32. VENTRICLES OF THE BRAIN

33. SPINAL CORD
🞇It is an elongated cylindrical structure that is a
ropelike bundle of nervous tissue
🞇In adults, it averages about 1.8 cm thick and 45
cm long
🞇It begins as a continuation of the medulla
oblongata at the level of the foramen magnum
🞇The spinal cord serves three principal functions:
Conduction, Locomotion and Reflexes
🞇The cord gives rise to 31 pairs of spinal
nerves. the part supplied by each pair of spinal
nerves is called a segment.
🞇The spinal cord is divided into cervical,
thoracic, lumbar, and sacral regions.

34. STRUCTURE OF THE SPINAL CORD
(Surface Anatomy)

35. CROSS-SECTIONAL ANATOMY
🞇The spinal cord consists of two kinds of
nervous tissue called gray and white
matter.
🞇Gray matter has a relatively dull color
because it contains little myelin.
🞇It has butterfly- or H-shaped in cross
sections
🞇It contains the somas, dendrites, and
proximal parts of the axons of neurons.
🞇It is the site of synaptic contact between
neurons (information processing)

36. GRAY AND WHITE MATTER

37. 🞇White matter contains an abundance of myelinated
axons, which give it a bright, pearly white
appearance.
🞇It is composed of bundles of axons called tracts or
fascicule
🞇It carry signals from one part of the CNS to another.
🞇The spinal cord has two tracts;Ascending and
descending tract
🞇Ascending tracts carry sensory information up the
cord and descending tracts conduct motor
impulses down

38. TRACT OF THE SPINAL CORD

39. PERIPHERAL NERVOUS SYSTEM
🞇The (PNS) is that portion of
the nervous system outside
the central nervous system
🞇Sensory receptors within the
sensory organs, neurons,
nerve, ganglia, and plexuses
are all part of the PNS
🞇The nerves of the PNS are
classified as;
 cranial nerves or spinal nerves,

40. GENERAL ANATOMY OF
NERVES AND GANGLIA
🞇A nerve is a cordlike organ composed of
numerous nerve fibers (axons) bound together
by connective tissue.
🞇Nerve fibers of the peripheral nervous system
are ensheathed in Schwann cells, which form a
neurilemma and often a myelin sheath around
the axon. Nerves has:
🞇 endoneurium, perineurium and epineurium

41. ANATOMY OF A NERVE

42. CRANIAL NERVES
🞇Cranial nerves are nerves that emerge directly
from the brain and the brainstem.
🞇There are 12 pairs of cranial nerves, numbered I
to XII
🞇They relay information between the brain and
parts of the body.
🞇 Considers to be parts of both CNS and PNS
🞇They are traditionally classified as sensory,
motor or mixed base on their functions.

43. CRANIAL NERVES

44. FUNCTIONS OF CRANIAL NERVES

45. SPINAL NERVES
🞇 There are 31 pairs of spinal nerves: 8 cervical
(C1–C8), 12 thoracic (T1–T12), 5 lumbar
(L1–L5), 5 sacral (S1–S5), and 1 coccygeal
(Co).
🞇 The first cervical nerve emerges between the
skull and atlas
🞇The others emerge through intervertebral
foramina, including the anterior and posterior
foramina of the sacrum and the sacral hiatus.

47. AUTONOMIC NERVOUS SYSTEM (ANS)
🞇 ANS is motor nervous system that controls
glands, cardiac muscle, and smooth muscle
🞇 The primary target organs of the ANS are the
viscera of the thoracic and abdominal cavities
🞇 Its job is to regulate such fundamental states
and life processes as heart rate, blood
pressure, body temperature, respiratory
airflow, pupillary diameter, digestion,
energy metabolism, defecation, and
urination.

48. DIVISION OF THE ANS
🞇The ANS has two subsystems
🞇Sympathetic
🞇parasympathetic divisions
🞇Sympathetic (Thoracolumbar) Division
The sympathetic division is also called the
thoracolumbar division
🞇It has relatively short preganglionic and
long postganglionic fibers

49. PARASYMPATHETIC DIVISION
🞇The parasympathetic division is also
called the craniosacral
🞇Somas of the preganglionic neurons are
located in the pons, medulla oblongata,
and segments S2 to S4 of the spinal cord
🞇The parasympathetic division has long
preganglionic fibers reaching almost all
the way to the target cells
🞇short postganglionic fibers that cover the
rest of the distance.

50. Thanks For Your Attention