The Human Nervous System

3 Vertebrate Brains Evolutionists contend that the brain is actually just a highly modified anterior region of the spinal cord

5 Vertebrate Brains Point at which the spinal cord ends and the brain begins has been chosen arbitrarily (since no sudden change in appearance occurs at this point). [more depth later]

6 Central Nervous System () Coordinates the activities of the body – Vertebrates have a dorsal CNS enclosed in skull, vertebrae

Embryonic Development of the Spinal Cord Wd-o#t=15

Spinal cord is a of neurons that runs from the base of the skull (foramen magnum) to the tip of the spinal column Protected by the in the spine Transmits nerve signals between the and relays back motor, organ and gland instructions Spinal Cord

Spinal cord is made of neurons SC is protected by the vertebral column and

11 Spinal Cord X-section Grey butterfly on a white background 2 Types of Nerve Tissue: White Matter is made up of ascending and descending tracts of neurons Grey Matter is composed of nerve cell bodies that are composed of interneurons

Different sections of the SC service different sections of the body Damage done to sensory neurons in C7 and C8 would have what affect on the body? 3. Why does a EMS check for spinal damage from the feet upward? Spinal Nerves

The Central Nervous System The brain and spinal cord are protected by the,the, and the skull and spinal column (vertebrae). The meninges are layers of tissue that protect the brain and spinal cord.

The Central Nervous System The brain and spinal cord themselves are composed of myelinated neurons (matter) and unmyelinated neurons (matter). Brain cross section Spinal cord cross section grey matter white matter

The Human Brain The fluid allows the SC and brain to be protecting them from blows or other trauma. Inside the skull the CSF is contained by the which covers the brain. Any trauma or tear in the dura can allow the fluid to leak out creating an emergency situation. Meninges is a 3-layered membrane that completely surrounds the brain and spinal cord offering further protection and organization.

The Human Brain Easily the most complex and highly organized structure on this planet grams ( ~3 lbs.) with a consistency of semi-soft cheese Neurons can be so densely packed that a cm 3 contains ~ 6 million cell bodies Vertebrate brain has embryological beginnings as a series of 3 hollow bulges at the anterior end of the spinal column

3 distinct parts of the brain: 1.Forebrain: a) (left and right hemisphere) b) (relay station) c) (internal equilibrium) 2.Midbrain 3.Hindbrain: a) b) c)

Hindbrain The hindbrain is composed of the, medulla oblongata and. The hindbrain and midbrain have fused together to form the

a) Medulla Oblongata Part of the brain extending from the to the Connection between PNS and CNS Controls many involuntary responses (nervous system); – Breathing muscles – Diameter of blood vessels – Sorts and relays info. Damage to this portion of the brain is often

Cerebellum Part of the Consists of lobes and is concerned with muscular coordination and maintenance of The act as a centre for information moving to and from the cerebellum and medulla

Pons (“") Between the midbrain and the medulla Contains nerve fibre tracts which connect the cerebellum and the cerebrum with the rest of the brain (relay station between different parts of brain)

24 Midbrain The midbrain is part of the brainstem.

Midbrain Primarily a and center Located below the center of the cerebrum Forms part of the brainstem (together with the pons and medulla)

Forebrain Includes the and hypothalamus (involved in the external and internal environment) as well as the cerebrum. Cerebral cortex, is composed of grey matter, and is thought to be the source of human.

a. Thalamus Sits at the of the forebrain Large mass of grey matter that runs along the sides of the brainstem The between the brainstem and the higher brain centres receives incoming receptors such as the eye, ear and skin

H ypothalamus (below/thalamus) Contains neurons responsible for the actions associated with hunger, thirst, pleasure, pain, sex drive and anger Directly connected to the most important gland of the body (– controls many other glands -> ) Motor center for integration of the nervous system and the system Contains the “" of mammals Maintains

Forms the part of the forebrain The cerebrum is divided in to, the right and left hemispheres. Beneath the cerebrum is the a band of fibres that transmit information between the right and left hemispheres of the cerebrum The dividing point is a deep grove called the. The hemispheres also consist of many other parts such as the lobes. Functions: Cerebrum

The surface of the cerebrum is called the The cerebral cortex has deep folds called fissures  surface area Cerebrum

The different sides of the cerebrum do different things for the opposite sides of the body. The right side of the cerebrum controls things such as imagination and 3-D forms.  The other side of the brain, the left side, controls numbering skills, posture, and reasoning.  Left Brain, Right Brain

34 Lobes of the Cerebrum Specific areas of the cerebral lobes control specific functions while other functions are much less localized (Example: intelligence)

Lobes of the Cerebrum 4 pairs of lobes of the cerebrum 1. Frontal - at the front (thought & movements, speech) 2. Temporal - at the sides (and speech) 3. Parietal - top and back (touch,) 4. Occipital - low at the back ()

A stroke results from damage to the brain resulting from a disruption of the Can causeloss of brain function Epileptic Seizure: uncontrolled storm of that sweeps over the cerebral cortex  entire cortex trying to do everything at once A Stroke powerful_stroke_of_insight.html

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