The Nervous System: Exploring the Brain and Its Functions, Slides of Biology

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The Nervous System

Dr. Arzu GÜRSOY ERGEN Research Asist. Duygu Berdi

Sensory input – gathering information

•To monitor changes occurring inside and

outside the body

Integration - To process and interpret

sensory input and decide if action is

needed

 Motor output

•A response to stimuli

•Activates muscles or glands

Functions of the Nervous System

Central Nervous System

• consists of the brain and spinal cord.
• Relays responses to these messages to your muscles and glands as your body responds to changes in your environment. Peripheral Nervous System - is made up of nerves that branch out from the central nervous system to muscles, skin, internal organs, and glands. - Sense organs continually send messages, such as odors, sights, or tastes, to your brain.

• All parts of the nervous system lying outside the brain and spinal cord.
• The sensory and motor neurons that connect to the CNS
• Function = to carry info between organs of the body and the CNS
• Humans have
• 12 paris of cranial nerves (sensory/motor/mixed) which control the head, face, neck, shoulders
• Except VAGUS nerve – controls internal organs
• – 31 pairs of spinal nerves (mixed) which take impulses to and from the spinal cord

Peripheral Nervous System (PNS)

• The basic unit of structure and function in

the nervous system

• Cells that conduct impulses.
  • Made up of dendrites, cell body and an axon

NEURONS

Neuron Structure Dendrite Dendrites carry nerve impulses toward a neuron’s cell body. Cell Body The cell body controls the cell’s basic functions. Axon Impulses travel along axons toward other cells. Myelin Sheath Some axons are covered by a myelin sheath that increases the speed of an impulse. Synapse The junction between an axon and another cell is a synapse. Chemicals called neurotransmitters pass the impulse from the sending neuron to the receiving cell.

• The mass of nerve tissue that acts as the control

center of the body is called the brain.

• Human brain weighs about 1300 – 1400 gr.
• Can store more information that all the libraries in

the world put together

• Creates ideas and controls thinking, reasoning,

movement, and emotions

• The brain has 3 major parts:
  • The cerebrum
  • The cerebellum
  • The brain stem

Central Nervous System: The Brain

Dura Mater (Hard Membrane): It is the outer membrane of the brain. It protects the brain from mechanical effects, injury and damage. Arachnoid Mater (Spider-like membrane ): It is located between the hard membrane and the thin membrane. It connects the hard membrane with the thin membrane. Pia Mater (Thin membrane ): It is the innermost membrane. It has abundant blood vessels in its structure. These blood vessels feed the brain.

Somatic Nervous System

• It is the nervous system consisting of motor and sensory nerves that direct voluntary movements under the control of the brain.
• It controls conscious behaviors such as writing and running by regulating the work of skeletal muscles.
• The somatic nervous system is responsible for the communication between the body and the external environment. Autonomus Nervous System
• Sympathetic and money sympathetic episodes They show opposite work. Parasympathetic ones are close to the target organ, and sympathetic ones are far away.
• The sympathetic system also enables the organism to react in stressful situations such as fear, anger, terror, excitement, and severe pain.
• The parasympathetic nervous system slows down our movements

Brain dissection

1. Notice that the brain has two halves, or hemispheres.
2. Can you tell the difference between the cerebrum and the cerebellum?
3. Do the ridges (called gyri) and grooves (sulci) in the tissue look different? How does the surface feel?
4. to slice through the brain along the center line, starting at the cerebrum and going down through the cerebellum, spinal cord, medulla, and pons. Separate the two halves of the brain and lay them with the inside facing up.
5. Use the labeled picture to identify the corpus callosum, medulla, pons, midbrain.
6. Look closely at the inside of the cerebellum. You should see a branching ‘tree’ of lighter tissue surrounded by darker tissue. The branches are white matter, which is made up of nerve axons. The darker tissue is gray matter, which is a collection of nerve cell bodies.
7. Try to find the lobs