THE BRAIN and Spinal Cord

9.12 Meninges 1. Layered membrane between skull and of tissue of the CNS 2. 3 layers: -Dura Mater -Arachnoid -Pia Mater

dura mater Outer most layer Tough white fibrous connective tissue Many blood vessels and nerves

Subdural hematoma: collection of blood outside the brain. usually caused by severe head injuries. bleeding causes increased pressure on the brain can be life-threatening Some subdural hematomas stop and resolve spontaneously; others require surgical drainage.

Dura mater around spine Forms strong tubular sheath around spinal cord EPIDURAL: Medication is delivered through a catheter inserted into the epidural space just outside the membrane that surrounds spinal cord and spinal fluid. It is the most commonly used method of pain relief for labor in the United States.

Arachnoid mater and pia mater Arachnoid: is attached to under side of dura mater and above the pia mater Pia mater: very thin Many nerves and blood vessels that nourish brain and spinal cord Cerebral spinal fluid circulates in subarachnoid space located between arachnoid and pia mater

9.13 Spinal cord Consists of 31 segments each gives rise to a pair of Begins where nervous tissue leaves the cranial cavity at the level of the foramen magnum Consists of 31 segments each gives rise to a pair of nerves nerve pairs are part of PNS Connect PNS to CNS

2 major functions of spinal cord Conduct impulses Center for reflexes Ascending tract: Carry sensory to brain

Descending tract Carry MOTOR instruction FROM brain

Brain

DEFINITION: The part of the CNS located within the skull, composed of 100 billion multipolar neurons, weighs 3 pounds Divided into 4 major portions

FUNCTION primary receiver, organizer and distributor of information for the body

Cerebral surface Fissure: deep groove

75% of all neuron cell bodies in the nervous system Cerebral surface (ridges) (grooves) 75% of all neuron cell bodies in the nervous system Myelinated axons, connect cell bodies with other parts of the nervous system

Cerebral cortex Functions: 1.Sensory- -interpret impulses from sensory receptors -produce feelings or sensations 2.Association – -connect sensory with motor -analyze and interpret sensory experiences -oversee memory, reasoning, judgment, verbalizing, & emotion 3. Motor- -lie in frontal lobe -axons cross from right to left control opposite side of body

Cerebrum (7/8 of human brain) Associated with higher brain functions such as thought and action. Interprets sensory info Initiates voluntary muscular movement Stores information (MEMORY) and reasons Responsible for Intelligence and personality

Named after skull bones they underlie! Divided into 4 lobes Named after skull bones they underlie!

Cerebrum largest and most complex part of the brain Divided into left and right hemispheres, separated by duramater corpus callosum: provides communication between the right and left cerebral cortices

Left hemisphere Right hemisphere Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two hemispheres.

Hemisphere Dominance Most people have Dominant LEFT controls: speech writing & reading Broca’s area in dominant hemisphere controls muscles in speaking Non dominant specializes in nonverbal functions such as: motor tasks understanding and interpreting musical patterns controls emotional and intuitive thinking

Ventricles Are interconnected cavities within cerebral hemispheres & brainstem Spaces are continuous with central spinal canal Contains cerebral spinal fluid

Cerebral Spinal Fluid Functions in: support & protection Maintains: stable ionic concentration IN CNS Provides pathway to blood for wastes

Diencephalon- mostly gray matter contains 1. Thalamus -interprets all senses except smell(central relay station) -synapses for voluntary movement 2. Hypothalamus -maintains homeostasis -controls heart rate, BP, temperature etc.. -coordinates the nervous and endocrine system

Spinal cord

Brain stem:Responsible for basic life functions such as Breathing Heartbeat Blood pressure Scientists say that this is the "simplest" part of human brains because a reptiles (who appear early on the evolutionary scale) entire brain resembles our brain stem.

Cerebellum (Little brain) 4 -associated with regulation and coordination of movement, posture, and balance

Cranial nerves 12 pairs Most are mixed containing sensory and motor neurons Some associated with senses and are sensory only learn names and what they do row row row your boat

learn names and what they do row row row your boat

Sensory Motor or Both