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Nervous System. Cells of the Nervous System Neurons Dendrites Axons – Schwann cells Synapse Supporting cells – Glial cells – Astrocytes – Oligodendrocytes.

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Presentation on theme: "Nervous System. Cells of the Nervous System Neurons Dendrites Axons – Schwann cells Synapse Supporting cells – Glial cells – Astrocytes – Oligodendrocytes."— Presentation transcript:

1 Nervous System

2 Cells of the Nervous System Neurons Dendrites Axons – Schwann cells Synapse Supporting cells – Glial cells – Astrocytes – Oligodendrocytes.

3 Central vs. Peripheral Nervous System Cell bodies = central nervous system (brain and spinal cord) Ganglia Ganglia + axons = peripheral nervous system

4 Types of Neurons Sensory Motor Interneurons – connect peripheral neurons with CNS neurons

5 Transmission Along Neurons The Resting Potential: Cell membrane is negative (polarized). Membrane stores energy by holding charges apart. – Positive outside and negative inside. Resting potential of a cell = -70 millivolts

6 Transmission (cont.) Sodium-potassium pumps on membrane – ATP driven Change in resting potential = a stimulus If stimulus depolarizes cell = Action Potential The action potential is an all or none event – A neuron has a threshold potential -50 millivolts

7 The Brain Contains cavities (ventricles) Cerebrospinal fluid (CSF) Meninges – 3 tough layers that protect brain and spinal cord – Dura mater – Arachnoid mater – Pia mater

8 Central Nervous System (CNS) 1. Medulla Oblongata - controls involuntary and visceral activities. 2. Cerebellum - controls body balance, muscular coordination and equilibrium. 3. Hypothalamus - maintains the internal environment. 4. Thalamus - Sorts out and relays the incoming and outgoing impulses. 5. Cerebral cortex - center of all voluntary muscular control and mental activity

9 Autonomic Nervous System Control of the involuntary muscles 2 separate parts – sympathetic – parasympathetic

10 Sympathetic vs. Parasympathetic SympatheticParasympathetic HeartSlows downSpeeds up ArteriesDilates (opens)Constricts Digestive OrgansSpeeds up peristalsis Slows down peristalsis Bronchial MusclesConstrictsDilates Sweat GlandsDecreases actionIncreases action

11 The Eye

12 Parts of the Eye 1. Cornea - protection 2. Aqueous Humor - helps focus light onto the retina 3. Iris - regulates amount of light entering the eye 4. Lens - focuses light onto the retina 5. Vitreous Humor - helps focus light onto the retina

13 Parts of the Eye (cont.) 6. Retina - transmit signals to the optic nerve 7. Rods and Cones - sense to light 8. Fovea - contains the highest concentration of cones 9. Optic nerve - connects the eye to the brain 10. Blind spot – no receptors, the eye is attached to the optic nerve here

14 The Ear

15 Parts of the Ear 1. Pinna – gathers sound 2. Outer ear - connects outer ear with ear drum (tympanic membrane) 3. Tympanic membrane - transmits sound waves to three tiny bones 4. Hammer, anvil, and stirrup (middle ear) - send impulses to the oval window of the cochlea. 5. Semicircular canals (inner ear) – balance 6. Cochlea - change sound waves into nerve impulses


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