Nervous System

Senses

The types of receptors based on stimulus type

The types of receptors based on stimulus origin

The eye

Olfaction

Gustation

The ear

Nervous system organization

Central nervous system (CNS)

Peripheral nervous system (PNS)

Somatic division

Autonomic division
(visceral)

Anatomy of
nervous system

Nerve components

Glial cells

Neurons

Major components
of a neuron

structural types of neurons

Functional types of neurons

Exteroceptors

Interoceptors

Proprioceptors

  • Stimulus origin is muscles (including tendon), ligament, and joints
    Ex: When closing the eyes, we got signal from out muscles
  • Stimulus comes from environment
  • Location: skin, special senses
  • Stimulus origin is internal organs
    Ex: we can feel our stomach when we ate too much

Thermoreceptor

  • Cold and warm receptor

Photoreceptor

  • Light with exteroceptor

Chemoreceptor

  • Sensitive to chemical

Nociceptor

  • Painful

Mechanoreceptor

  • Touch, pressure, vibration, stretch

Baroreceptor

  • Measure blood pressure

Eye components

Visual pathway

Fibrous layer

  • Sclera: white, dense connective tissue
  • Cornea: clear- allows light into the eye

Vascular layer

  • Choroid: nourishes the other layers

Inner layer

  • Retina: photoreceptor- axons
    converge to form optic nerve

Cornea

Pupil

Lens

(Posterior segment- vitreous humor)

Retina

Component

Olfactory epithlium

Pathway

Olfactory receptors

Olfactory sensory neuron
within the olfactory bulb

Olfactory tract

Limbic system

Primary olfactory cortex in temporal lobe

  • Roof of the nasal cavity
  • Pseudostratified columnar epithelium

Components

Pathway

Taste buds

  • Tongue, inner checks, posterior wall of pharynx, and epiglottis
  • Epithelial cells

Medullar ublongata

Thalamus

Gustatory cortex in the insula

3 cranial nerves

  • Facial nerve (VII)
  • Glossopharyngeal nerve (IX)
  • Vagus nerve (X)

Components

Pathway

Outer layer

  • Auricle (pinna): gather sound waves
  • External acoustic meatus: running medially
    from the auricle to ear drum

Vestibular nerve and cochlear nerve

Middle layer

  • Tympanic membrane (ear drum)
  • Auditory ossicles: malleus, incus, and stapes

Inner layer (labyrinth)

  • Semicircular canal
  • Vestibule
  • Cochlea

Internal acoustic meatus

Vestibulocochlear nerve VIII

Cochlea banch of CN VIII

Medulla oblongata

Pons

Midbrain

Thalamus

Primary auditory cortex in temporal lobe

Functions

Main structures

  • Brain
  • Spinal cord
  • Receive and process incoming signal
  • Respond

Main structures

Functions

  • Cranial nerves: attached to brain
  • Spinal nerves: attached to spinal cord
  • Ganglia: cluster/group of neuron cell bodies
  • Be sensitive to stimuli and send that information toward CNS
  • Output to skeletal muscle
  • Mainly to contents of ventral body cavity
  • Smooth muscle: digestive system, respiratory system, reproductive system, arrector pili muscle of skin, and sweat glands
  • Glands
    Blood vessel walls (smooth muscle)
  • Cardiac muscle

Central nervous system

Peripheral nervous system

Astrocytes

Microglia (phagocytes)

Oligodendrocytes

Ependymal cells

  • Most numerous
  • Many processes that contact neurons
    and capillaries (smallest blood vessels)

Satellite cells

Schwann cells

  • Remove microbes and
    damaged nerve tissue
  • Wrap their plasma membranes
    around one portion of several axon
  • Simple cuboidal/columnar epithelium
    with cilia that keep CSF moving
  • Lining spaces filled with cerebrospinal
    fluid called ventricles
  • Structurally supportive
  • Regulates exchange of materials
    in/out of neuron cell body
  • Wrap plasma membrane around
    one portion of one axon
  • Being supported
  • Cell body
  • Nucleus and nucleolus
  • Chromatophilic substance
  • Dendrites
  • Axon hillock
  • Axon
  • Axon collaterals
  • Terminal arborization
  • Terminal boutons (axon terminals)

Motor
(efferent neurons)

Sensory
(afferent neurons)

Interneurons
(association neurons)

  • Multipolar
  • Cell bodies in CNS
    --> muscle and glands
  • Unipolar
  • Bipolar: special sensory
  • Cell bodies located in ganglia of PNS
  • Between neuron in CNS
  • multipolar
  • 99.98% of all neurons in the body

Multipolar

Bipolar

Unipolar
(pseudounipolar)

  • Three or more processes
  • Found in the CNS
  • Single axon and dendrite
  • Found only in some special
    sense organs
  • One process attached to the cell body
  • Cell body appears to divide the axon
    into parts (peripheral & central process)

Axon

  • Nerve fiber

Myelin

  • Around each axon

Endoneurium

  • Around myelin sheath

Perineurium

  • Around the bundle of axons

Fascicle

  • Bundle of axons

Epineurium

  • Outer most layer
  • Surrounding multiple nerve
    fascicles and blood vessels