Compendium Five

I. Nervous System

• A. Overview of the Nervous System
• B. The Central Nervous System
• C. The Limbic System and Higher Mental Functions
• D. The Peripheral Nervous System
• E. Drug Abuse
  

II. Senses

• A. Sensory Receptors and Sensations
• B. Proprioceptors and Cutaneous Receptors
• C. Senses of Taste and Smell
• D. Sense of Vision
• E. Sense of Hearing
• F. Sense of Equilibrium
  

I. The Nervous System

A. Overview of the Nervous System

• Central Nervous System (CNS) (Brain and Spinal Cord)

• Peripheral Nervous System (PNS) (Nerves)

• 3 Functions

1. Sensory receptors generate nerve impulses that travel through CNS and PNS

2. CNS performs integration

3. CNS generates motor output

• Nervous Tissue

Neurons (cell transmit nerve impulses)

Neuraoglia (support and nourish)

• Neuron Structure

---3 types of neurons---

1. Sensory Neurons

2. Sensory Receptors

3. Interneurons

---Vary in appearances: 3 common parts---

1. Cell Body (nucleus)

2. Dendrites (receive signals)

3. Axon (conducts nerve impulses)

• Myelin Sheath

Cover and protect axons

Node of Ranvier- breaks in axons

Only present on long axons

• Nerve Impulse

Resting Potential (not conducting impulse, sodium and potassium pump)

Action Potential (Change in polarity, Sodium gates (depolarization), Potassium Gates (re polarization)

• Propagation of an Action Potential

Saltatory Conduction

MS and Leukodystrophies

Lorenzo's oil

• Synapse
  

Events that occur:

1. Nerve impulse reach axon terminal

2. Calcium enters terminal

3. Neurotransmitter released and diffuse

There are 100 known Neurotransmitter molecules known

Synaptic Integration: summing up of signals

B. The Central Nervous System

• The Spinal Cord

---Structure of Spinal Cord---

Central Canal- cerebrospinal fluid

Gray Matter- H Shaped

White Matter- Inside the gray matter

---Functions---

Communication from the brain to the nerves

Reflex actions

• The Brain
  

4 Ventricles

---Cerebrum---

telencephalon

largest portion of the brain

2 halves

longitudinal fissure separates the hemispheres

Frontal Lobe- Forehead

Parietal Lobe- Dorsal to the frontal

Occipital Lobe- Dorsal to parietal

Temporal Lobe- Temple and ear

Cerebral Cortex is the out layer of the brain

(http://en.wikipedia.org/wiki/Image:Brainlobes.svg)

---Diencephalon---

hypothalamus and the thalamus

---Cerebellum---

under the occipital region

2 portions- white matter

receives sensory input (eyes, ears, joints, muscles)

motor output from cerebral cortex

sends motor impulses to skeletal muscles

---Brain Stem---

Midbrain- Relay station

the Pons- Bundles of axons

Medulla Oblongata

C. The Limbic System and Higher Mental Functions

• The Limbic System

Primitive emotions and higher mental functions

Amygdala- emotion and sense of fear

Hippocampus- learning and memory

Higher Mental Functions

---Memory---

Short term memory

Long term memory

Sematic Memory (numbers and words)

Episodic Memory (persons, events,)

Skill Memory

---Language and Speech---

Depends mostly on Sematic Memory

D. The Peripheral Nervous System

nerves are composed of axons

12 pairs of cranial nerves (sensory and motor)

---Somatic System---

Skin, skeletal muscles, tendons

Reflexes (automatic response to stimulus)

---Autonomic System---

Regulates activity of cardiac and smooth muscles

---Both Systems---

1. Function automatically and involuntary

2. Innervate all internal organs

3. 2 neurons and 1 ganglia

Produce sympathetic division and Parasympathetic Division

E. Drug Abuse

• Alcohol (liver and brain; depressant; memory loss)
  Nicotine (stimulant; increase heart rate and blood pressure)
• Cocaine (stimulant; cardiac and respiratory arrest)
• Methamphetamine (stimulant; paranoia, hallucinations)
• Heroin (depressant; injected, snorted or inhaled)

II. Senses

A. Sensory Receptors and Sensations

• Dendrites
• Extereceptors (outside of body)
• Intereceptors (inside the body)
• Types of sensory receptors

Chemoreceptors--Chemicals

Pain Receptors

Photoreceptors--Light Energy

Mechanoreceptors--Mechanical

Thermoreceptors--Changes in Temperature

• Sensations occurs when sensory receptors initiate the nerve impulses and then they integrate

B. Proprioceptors and Cutaneous Receptors

• Proprioceptors (equilibrium, posture, and muscle tone)


• Cutaneous Receptors (dermis; touch, pressure, pain; Meissner Corpuscles; Merkel Disks, and root of hair)
• Pain Receptors (nociceptors)
  

C. Senses of Smell and Taste

• Sense of taste



• 3000 Taste buds

4 Primary tastes (sweet, sour, bitter, salty)

The Brain takes the average of tastes to get an average

• Sense of smell

80-90 % of taste is a result of smell

Olfactory Cells

D. Sense of Vision

• Anatomy and Physiology of the Eye

2.5 cm in diameter

sclera-white part of eye

cornea- "windows the eye"

choroid- absorbs stray light rays

iris- regulates the size of pupil

pupil- center of the iris which light enters

ciliary body- controls the shape of lens for near or far vision

lens-refracts and focus light rays

retina-contains rods (dark) and cones (bright light)

E. Sense of Hearing

• Anatomy and Physiology of the ear

Outer ear (pinna and auditory canal)

Middle Ear (tympanic membrane; oval and round window; malleus, incus, and stapes; auditory tube)

Outer Ear (semicircular canals, vestibule, cochlea)

Waves enter the auditory canal, the malleus moves back and forth, passed to the incus, when stapes strikes the membrane the waves move

E. Sense of Equilibrium

• Rotational Equilibrium
  



• Gravitational Equilibrium