Download Human Nervous System

Human Nervous System
Human Nervous System
Central Nervous System (CNS)
-Brain and spinal cord
- interneurones
Peripheral Nervous system (PNS)
-Everything else (cranial and spinal nerves)
-Sensory and motor neurons
Somatic Nervous System
- Voluntary
- Input from sense organs
- Output to skeletal muscles
Autonomic Nervous System
- Involuntary
- Input from internal receptors
- Output to smooth muscles and glands
Sympathetic Motor System
-`Fight or Flight` response
- Neurotransmitter: Noradrenaline
- `Adrenergic System`
Parasympathetic Motor System
- Relaxing responses
- Neurotransmitter: Acetylcholine
- `Cholinergic System`
Human Nervous System
Human Nervous System
Parts of Nervous System:
I- Central Nervous system
* Brain
* Spinal Cord
II- Peripheral Nervous System:
* Cranial Nerves
* Spinal Nerves
Human Nervous System
Parts of Nervous
System:
I- Central Nervous system
* Brain
* Spinal Cord
Human Nervous System
Parts of Nervous
System:
II- Peripheral Nervous System:
* Cranial Nerves
* Spinal Nerves
Human Nervous System
Parts of Nervous
System:
II- Peripheral Nervous System:
* Cranial Nerves
* Spinal Nerves
Human Nervous System
I- Central Nervous system
Brain
• Is the primary center for regulation and coordination of body
activities.
• Each portion of the Brain controls different aspects of body
function.
• The Brain is organized so that the left side of the Brain
controls the right side of the body and the right side of the
Brain controls the left side of the body
Human Nervous System
Parts of the Brain
1. Forebrain
2. Midbrain
3. Hindbrain
Human Nervous System
Spinal cord
• Spinal cord carries all the
nerves that affect the limbs and
lower portion of the body.
• It is the pathway for impulses
going to and from the Brain.
Human Nervous System
Cerebrospinal Fluid (CSF)
• CSF flows throughout the Brain and the spinal cord
• Its primary function is to cushion these organs from shock
and injury.
Human Nervous System
Parts of Nervous System:
II- Peripheral Nervous System:
* Cranial Nerves
* Spinal Nerves
• The cranial nerves are arranged in 12 pairs, so the two nerves on a
pair are identical in function and structure.
• These nerves serve both sensory and motor functions.
Human Nervous System
The 12 Cranial Nerves
•The cranial nerves are generally named for the area or function they serve
and are identified with Roman numerals.
1.
I - Olfactory
2.
II - Optic
3.
III - Oculomotor
4.
IV - Trochlear
5.
V - Trigeminal
6.
VI - Abducens
7.
VII - Facial
8.
VIII - Auditory
9.
IX - Glossopharyngeal
10. X - Vagus
11. XI - Accessory
12. XII - Hypoglassal
Human Nervous System
Human Nervous System
II- Peripheral Nervous System:
* Cranial Nerves
* Spinal Nerves
1. Cervical nerves
2. Thoracic nerves
3. Lumbar nerves
4. Sacral nerves
Human Nervous System
Structure of the Nervous system
•
The basic cells of the nervous system are the Neurons
•
They are composed of a cell body and neural process
(nerve fibers)
Types of nerve cells
1. Sensory neurons
2. Motor neurons
Human Nervous System
Types of nerve cells
1. Sensory neuron:
* Afferent Neuron– Moving away from a central organ or point.
* Relays messages from receptors to the Brain or Spinal cord.
Human Nervous System
Types of nerve cells
2. Motor neuron:
* Efferent Neuron– Moving towards a central organ or point.
* Relays messages from the Brain or Spinal cord to the muscles and
organs.
Human Nervous System
Interneuron (relay neurone):
* Relays messages from sensory neurone to motor neurone
* Make up the Brain and Spinal cord
Human Nervous System
Synapses
• Is the space between two neurons or between a neuron and a receptor organ.
Neurotransmitter
• Is a chemical substance that makes it possible for the impulse to jump across the
synapse from one neuron to another.
Human Nervous System
Schwann cells
• Most neurons have many companion cells called Schwann cells, which wrap
their cell membrane around the axon many times in a spiral to form a thick
insulating lipid layer called the Myelin sheath.
Human Nervous System
Myelin sheath
- Is the white protective covering of some nerves.
Human Nervous System
Myelin sheath
* If the nerve is covered with myelin it is referred to as the white matter.
* If the nerve is NOT covered with protective myelin sheath is called gray matter
which makes up the gray matter of the Brain and spinal cord.
Human Nervous System
Human Nervous System
Central Nervous System (CNS)
-Brain and spinal cord
- interneurones
Peripheral Nervous system (PNS)
-Everything else (cranial and spinal nerves)
-Sensory and motor neurons
Somatic Nervous System
- Voluntary
- Input from sense organs
- Output to skeletal muscles
Autonomic Nervous System
- Involuntary
- Input from internal receptors
- Output to smooth muscles and glands
Sympathetic Motor System
-`Fight or Flight` response
- Neurotransmitter: Noradrenaline
- `Adrenergic System`
Parasympathetic Motor System
- Rest and digest responses
- Neurotransmitter: Acetylcholine
- `Cholinergic System`
Human Nervous System
- Most body organs are innervated
by two separate sets of motor
neurons;
• one from the sympathetic system
• one from the parasympathetic
system
- These neurones have opposite
(antagonistic) effects.
Human Nervous System
The Autonomic Nervous System
Structure
Sympathetic Stimulation
Parasympathetic Stimulation
Iris (eye muscle)
Pupil dilation
Pupil constriction
Salivary Glands
Saliva production reduced
Saliva production increased
Oral/Nasal Mucosa
Mucus production reduced
Mucus production increased
Heart
Heart rate and force increased
Heart rate and force decreased
Lung
Bronchial muscle relaxed
Bronchial muscle contracted
Stomach
Peristalsis reduced
Gastric juice secreted; motility increased
Small Intestine
Motility reduced
Digestion increased
Large Intestine
Motility reduced
Secretions and motility increased
Liver
Increased conversion of
glycogen to glucose
Kidney
Decreased urine secretion
Adrenal medulla
Norepinephrine and
epinephrine secreted
Bladder
Wall relaxed
Sphincter closed
Increased urine secretion
Wall contracted
Sphincter relaxed
Human Nervous System
• It should be noted that the autonomic nervous system is always
working. It is NOT ONLY active during "fight or flight" or "rest
and digest" situations. Rather, the autonomic nervous system
acts to maintain normal internal functions and works with the
somatic nervous system.