Nervous SystemIdentify Principle Parts of the Brain

Identify the principle parts of the nervous system

Describe the cells that make up the nervous system

Describe what starts and stops a nerve impulse (action potential)

The role of neurotransmitters Compare the functions of the CNS & PNS Identify the principle parts of the brain

Objectives

Brain receives incoming info from spinal cord and nerves integrates/processes info and generates responses

3 anatomical & functional divisions1) Hindbrain – basic autonomic and vital tasks2) Midbrain – muscle groups, responses to

sights & sounds3) Forebrain – receives & integrates sensory

input & determines our more complex behavior

The Brain – command central

Figure 11.15

Connected to spinal column Oldest, most primitive brain division Most similar among animals Structures:1) Medulla oblongata2) Cerebellum3) Pons

Hindbrain – vital tasks

Controls autonomic functions◦ Heart rate◦ Blood pressure◦ Respiratory information – O2 & CO2 levels◦ Cough reflex◦ Swallowing◦ Sneezing◦ Vomiting

This is where the neurons cross over to the other side and the left brain controls the right side of the body and vice versa

1) Medulla oblongata

Located just behind the medulla oblongata and coordinates basic (unconscious) movements

Ensures that antagonistic muscles don’t contract at the same time

Stores sequenced information – tying shoes Receives sensory input from joint & muscle

receptors, balance & position receptors in ear and visual receptors

Excess alcohol disrupts these functions

2) Cerebellum

Located just above and partly surrounding the medulla oblongata

Contains groups of axons that extend from the cerebellum to the rest of the CNS &

Coordinates the flow of information between the cerebellum and the higher brain centers

Aids the medulla oblongata in regulating respiration

3) Pons

Visual & auditory sensory input passes through the midbrain before being relayed to the higher brain centers

Coordinates movements of the head related to vision and hearing (e.g. turning towards sound or flashing lights)

Controls eye movement and pupil size Monitors unconscious movement of skeletal

muscles (smooth moves) Reticular formation located here-neuron

bundle aids in posture, balance & muscle tone, level of wakefulness

Midbrain – vision & hearing

Emotions Conscious thought Parts:1) Hypothalmus2) Thalmus3) Limbic system4) Cerebrum5) Glands – 2 – pineal, pituitary

Forebrain – complex behavior

Located @ base of forebrain just above midbrain

Coordinates some autonomic fxns, pituitary gland, water & solute balance, T control, carbohydrate metabolism, breast milk production

Monitors sensory signals: sight, smell, taste, noise, body T

Hunger center Thirst center

1) Hypothalmus

Together w/hypothalmus maintains homeostasis & processes information

Accepts sensory signals & channels them to cerebrum for interpretation (e.g. thalmus may have a consciousness of pain but does not know the location of the pain – the cerebrum interprets the signal and we know where it hurts)

2) Thalmus – receiving, processing, transferring info

A group of neural pathways that connects parts of the thalmus & hypolthalmus & inner portions of the cerebrum

“border” – to describe structures that bordered the basal regions of the cerebrum – but has come to describe all neuronal structures that control emotional behavior and motivational drives

Limbic activities are monitored by hypothalmus and modified by cerebrum (social norms)

3) Limbic System – emotions & memory

Most developed brain region Language Decision making Conscious thought Left and right cerebral hemispheres are

connected in the middle by the corpus callosum = enables 2 hemispheres to share sensory-motor info

Cerebrum – human functioning

Consists of an outer layer of mostly gray matter (unmylenated CNS neurons, neuroglial cells)

Inner portion consists of white matter containing mylenated nerve axons connecting the lower brain area to the cerebral cortex

Cerebral Cortex

This structure - inner section of ascending and descending axons and an outer layer of cells – makes it ideally suited to ◦ direct incoming info to the proper brain region for

processing◦ Integrate and process info◦ Route outgoing motor activity to appropriate

areas of the body

Cerebral cortex structure