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Nervous System, Sensory system - Coggle Diagram
Nervous System
Effects on ageing
Structural changes
Brain atrophy
Reduction in brain volume and weight
Shrinkage of neurons
Decrease in number and size of neurons
Changes in neural connections
Synaptic connections may decline
Vascular changes
Reduced blood flow
Impaired oxygen and nutrient supply to the brain
Increased Risk of Stroke
Higher susceptibility to vascular events
Motor Function Changes
Muscle Weakness
Decreased muscle mass and strength
Slower Reflexes
Delayed response to stimuli
Neurodegenerative Diseases
Increased Risk of Alzheimer's Disease
Accumulation of beta-amyloid plaques and tau tangles
Parkinson's Disease
Degeneration of dopamine-producing neurons
Sensory Changes
Decline in Vision and Hearing
Degeneration of sensory receptors
Reduced Proprioception
Impaired sense of body position and movement
Central Nervous System [CNS]
Spinal cord
Tuber-like structure of neurons
Neurons
Anatomy
Soma
Dendrites
Axon
Transport
Axonal
Anterograde
Retrograde
microtubules guides
Supported by
Glial cells [neuroglia]
Central Nervous System
Oligodendrocytes
Astrocyctes
Microglia
Ependymal cells
Peripheral Nervous System
Satellite cells
Schwann cells
Properties
Excitability
Conductivity
Saltatory conduction
myelinated axons
unmyelinated axons
Regular conduction
Secretion
Classification
Function
Sensory
Motor
somatic
automatic
sympathetic
parasympathetic
Interneurons
Structure
Unipolar
Bipolar
Multipolar
Pseudounipolar
Communicate
by signals
Chemical signals
Neurotransmitter
excitatory
inhibitory
Electrical signals
through sypnases
Types
axosomatic
axodendritic
axoaxonic
Electrical sypnases
Gap junctions
Chemical sypnases
Ligan-gated channels
Vertebrae protect spinal cord
The brain
Brain stem
controls
voluntary movements
connects
brain with spinal cord
Cerebrum
largest part of the brain
controls
memory
language
process
touch
sight
Cerebellum
controls
voluntary movements
balance
posture
Score info about the movements you always do
Peripheral Nervous System [PNS]
Autonomic system
controls
smooth muscle
cardiac muscle
Involuntary movements
Sympathetic
'Fight or Flight'
Parasympathetic
'Rest and digest'
Somatic system
controls
skeletal muscle
voluntary movements
Sensory system
Special senses
Specialized Organs
Olfaction- Sense of smell
Structure of Olfactory Receptor Cells:
Olfactory receptor cells equipped with hair-like cilia.
Cilia aid in distinguishing among different odors
Olfactory Organs Location:
Olfactory organs located in masses of epithelium
Cover the upper part of the nasal cavity, superior nasal conchae, and part of the nasal septum
Mechanism
Involves olfactory receptors for the sense of smell
Interconnected with the sense of taste
Gustatory- Sense of taste
Taste Pores and Taste Hairs:
Taste pores contain tiny projections known as taste hairs
Taste hairs are the sensitive parts of taste receptor cells
Impulse Generation
Stimulation of taste receptors triggers impulses.
Impulses travel along nearby nerve fibers to reach the brain.
Interdependence of Taste and Smell:
About 80% of the sense of taste relies on the sense of smell
Nasal congestion can diminish the taste of food, as experienced during flu.
Five Primary Taste Sensations:
Sweetness, sourness, saltiness, bitterness, and umami (deliciousness)
These sensations form the basis for the perception of different flavors.
Auditory- Sense of hearing
Functions of the Human Ear:
Serves two sensory functions: detection of sound and detection of body position for maintaining balance
Structural Divisions of the Ear:
Divided into three parts: external (outer), middle, and inner ear.
Middle Ear Structures:
Includes auditory ossicles: malleus, incus, and stapes.
Ligaments and the oval window are also part of the middle ear
Inner Ear Structures:
Comprises the osseous labyrinth and membranous labyrinth.
Contains three semicircular canals, the cochlea, round window, and the organ of Corti.
External Ear
Auricle (Pinna):
Funnel-shaped structure composed of elastic cartilage.
Thin skin and small amounts of hair.
Function: Funnels sound waves to the external acoustic meatus
External Acoustic Meatus:
Passage leading into the ear.
Glands secrete cerumen (earwax), a yellow-brown waxy substance.
Cerumen traps foreign particles and repels insects from entering the ear.
Eardrum (Tympanic Membrane):
Semitransparent membrane.
Covered by thin skin on the outside and mucous membrane on the inside.
Moves back and forth in response to sound waves.
Serves as the boundary between the outer and middle ear.
Visual- Sense of sight
Function of Accessory Structures:
Important for the maintenance and protection of the eyes.
Serve various functions such as protection, lubrication, movement, and support for the proper functioning of the eyes.
Refraction:
Refraction is the bending of light waves to focus an image on the retina.
Two steps in focusing: through the cornea and then through the lens.
List of Accessory Structures:
Eyebrows
Serve a protective function.
Help divert sweat and other substances away from the eyes.
Eyelids
Also known as the palpebrae
Function to protect the eyes from foreign objects and excessive light.
Eyelashes
Short, fine hairs located on the margins of the eyelids.
Help prevent foreign particles from entering the eyes.
Conjunctiva
Thin, transparent membrane covering the inner surface of the eyelids and the anterior surface of the eyeball.
Provides lubrication and protection.
Lacrimal Apparatus
Includes the lacrimal glands and ducts.
Produces and drains tears to moisten and cleanse the eyes.
Extrinsic Eye Muscles
Muscles responsible for moving the eyeball within the eye socket.
Allow for precise control of eye movement.
Neuronal Pathways for Vision
Ganglion Cell Axons
Extend to the lateral geniculate ganglion of the thalamus.
Synapse occurs at the lateral geniculate ganglion.
Optic Radiations:
Neurons from the lateral geniculate ganglion form optic radiations.
Optic radiations project to the visual cortex.
Optic Chiasm:
Axons from the nasal retina cross in the optic chiasm.
Axons from the temporal retina remain uncrossed.
Projection to Cerebral Hemisphere:
Neurons from the nasal visual field (temporal retina) of one eye and the temporal visual field (nasal retina) of the opposite eye project to the same cerebral hemisphere.
General senses
Receptors all over thebody
Touch
Pressure
Position
Pain