Chapter 11,12,13

-Brain and Spinal Cord.

-Integration and control center.

-Interprets sensory input and dictates motor output.

Everything else:

Cranial nerve, spinal nerves, ganglia, enteric plexuses in small intestine, sensory receptors in skin.

-Somatic nervous system

-Autonomic nervous system

-Enteric nervous system

-Somatic and viscera sensory nerves fibers.

-Conducts impulses from receptions to the CNS.

Transmits impulses from CNS to effector organs:

Muscles and glands.

Two divisions: Somatic and Autonomic Nervous System.

Conduct impulses from CNS to skeletal muscles

Voluntary nervous system (Counscios control of skeletal muscles)

Consist of visceral motor nerve fibers.

Regulates smooth and cardiac muscles and glands.

Involuntary.

Two functional subdivision:

Sympathetic and Parasympathetic.

Mobilitizes body system during activity.

Conserves energy.

Salivation, Lacrimation, Urination, Digestion, Defecation.

Is master controling and communicating system body, via electrical and chemical signals.

-Sensory input

-Integration

-Motor output

Activation of effector organs (muscles and glands) produces a response.

-Are structural units of nervous system.

-Extreme longevity - 100 + years.

-Amitotic (except olfactory epithelium and hippocampus).

-High metabolic rate - require continuous and abundant oxygen and glucose.

-All have a cell body and one or more processes.

Contains nucleus, cytoplasm, typical organells and Nissl boddies.

Cluster of neurons cell bodies in the CNS

Receiving/ input portions.

Graded potentials.

Propagates nerve impulses.

Action potentials.

Action Potential generated here

Cone-shape part at cell body

No protein synthesis here.

-Many processes extend fron the cell body

-All are dendrites except for a single axon

-Most abundant in body

-Major neuron type in the CNS

-Two processes extend from the cell

-One is a fused dendrite, the other is an axon

-Rare

-Found in some special sensory organs like olfactory mucosa, eye and ear.

-One process extends from the cell body and forms cental and peripheral processes, which together comprise an axon.

-Found mainly in PNS

-Common only in dorsal root ganglia of the spinal cord and sensory ganglia of cranial nerves

-Astrocites

-Microglial cells

-Ependymal cells

-Oligodendrocytes

-Star shape

-Large and most abundant in CNS

Functions: Support, Nutrition and Blood Brain Barrier

-Support neurons with microfilaments and nutrition.

-Secrete chimicals to regulate growth, migration and interconnection among neurons in the embryo.

-Maintain a good chemical enviroment for generation Action Potentials.

Are proliferation of astrocytes when CNS axons are cut and won't regrow.

-Inmune like cells: Phagocytosis

-Found in CNS

-Functions as phagocytes to remove cellular debris and microbes.

-Found in CNS: CSF

-Line the ventricales of the brain and central canal of spinal cord.

-Secrete CSF (cerebrospinal fluit) which protects and nourishes the brain/spinal cord.

-Form blood-cerebrospinal fluit barrier.

-Satellite cells

-Schwann cells

-Found in PNS: Support, Nutrition

-Surround neuronal cell bodies to provide structural support.

-Regulates exchange of materials between neuronal cell bodies and interstitial fluid

-Found in the PNS: Myelin formation

-Form and maintain myelin sheath arounf PNS axons

-1 cell myelinates 1 axon

-Participate in axon regeneration

-Are a mulpitple lipoprotein covering

-It electrically insulates the axon and increases the speed of nerve impulses (AP) conduction.

-Nodes of Ranvier

Gaps in the myelin sheath.

Do not contain sheath

Conduct impulses more slowly

-Loss / destruction of myelin sheaths due to disorder or radiation/chemotherapy

-May cause deterioration of affected nerves.

1. A schwann cell envelops an axon

2. The schwann cell then rotates around the axon, wrapping its plasma membrane loosely around it in successive layers.

3. The schwann vell cytoplasm is force between the membranes. The right membrane wrapping surroundings the axon from the myelin sheath.

Conduction is slow because it takes time for ions and for gates of channel proteins to move, and this must occur before voltage can be regenerated.

Conduct is fast. Myelin keeps current in axons (voltage doesn't decay much). APs are generated only in the myelin sheath gaps and appear to jump rapidly from gap to gap.

Open in response to changes in membrane potential.

Open and close in response to phisical deformation of receptos, as sensory receptors.

Channels, which are always open

-Autoimmune demyelinating disease.

-Demyelinates CNS axons

-Turns them into ninfunctioning lesions called Scleroses.

-Impulses conduction ceases, but axons are nor damaged

-Cycles of remission and relapse are typical

-Symptoms: Visial & speech distrubances, muscle weakness/ tingling/ paralysis, incontinence.

There are two, one in each hemisphere. Horseshoe in appearance. Seperated by the Septum Pellucidum-thin membrane.

CSF reabsorbed by the Arachnoid granulation-project into veins of the dural sinuses.

3 connective tissue membranes that lie external to the CNS organs.

-Cover and protects the CNS, blood vessels and enclose venoues senuses.

-Contains CSF

"Tough Mother" The outer meningeal covering.

Two layers:

-Endosteal layer

-Meningeal layer

Fused with the periosteum in the cranial bones.

a.Dura sinus: Large blood sinus between the two laters. Drain blood from cranial venis into jugular veins.

1.The choroid plaxus of each ventricles produces CSF.

2.CSF flows the ventricles and into the subarachnoid space via the median and lateral apertures.

3.CSF flows through the subarachnoid space.

4.CSF is absorbed into the dural venous sinuses via the arachnoid granulations.

Cerebral hemisphere are paired (left and right) superior parts of the brain.

-Includes more than half of the brain mass.

-The surface is made of ridges (gyri)

and grooves (sulci).

1. Cortex (gray matter)

2. White matter

3. Basal nuclei (deep pockets of gray matter)

Fissures (deep grooves) divide the cerebrum into lobes.

Frontal, Parietal, Occipital, and Temporal Lobe.

Temporal lobe

Temporal lobe

(involved in the perception of taste).

Visceral Sensory Area: Posterior to gustatory cortex.

-Outer layer in the cerebral cortex; composed mostly of neuron cell bodies.

-Fibers tracts deeps to the grey matter.

-Corpus callosum connects hemisphere.

-Surround central canal.

-Forms butterfly or H shape

-Dominated by cell bodies neurons neuroglia. and unmyelinated axons.

-Great amount in spinal cord segments serving limbs

-Superficial

-Contains large numbers of myelinated and unmyelinated axons.

Outlines temporal lobe.

-Location: walls of the 3rd ventricle.

-Makes up to 80% of diencephalon.

-The sensory relay center on the body.

-Olfactory doesn't relay here.

-Relays most sensational to the cerebrum.

-Ascending fibers synapse here before entering to Cereberum.

-Many important nuclei are found here. Mostly grey matter.

-Nuclei cell bodies, for hearing, vision, taste.

-Key role in meditaion, motor activities, cortical arousal, learning and memory.

-Location: below the Thalamus.

-Control center of the ANS.

-Synthesizes, store and releases hormones.

-Regulates secretion from pituitary gland. The infundibulum connects Hypo. and Pituitary

-Temperature center.

-Coordinates heart rate, blood pressure, respiratory rate from Pons and Medulla.

-Regulates fear, anger, hunger, sexual feelings.

-Two visible bumps on the posterior of the Hypothalamus.

-Memory and emotional response to odors.

-Location: Above the Thalamus.

-Includes the Pineal gland.

-Control of the Circadian Rhythm (biological clock)

-Releases Melatonin (Hormone).

-Induces sleep. High levels during darkness.

-"Emotional Brain"

-Links conscious to the unconscious.

-Emotions, memory, mood, behavior, olfaction.

-Cingulate gyrus

-Hypothalamus

-Hippocampus

-Amygdala

-Olfactory bulbs

-Fornix

(Limbic lobe) Integration of sensory input, adds emotional content.

Contol center of ANS

Control emotions, fear, interprets facial expressions, new social situations, identifyng danger.

-Midbrain, Pons, Medulla Oblongata.

-Different form spinal cord due to having nuclei of gray matter embedded in the white.

-Produces programmed, automatic behaviors necessary for survival

-Positioned between cerebrum and spinal cord.

-Upper part of the brain stem.

-Origin for cranial nerves 3 and 4.

-"Bridge", relay station for descending and ascending fibers.

-Responsible for respiratory rhythm, inhalation and exhalation.

-Origin for cranial nerves 5 and 7.

-Becomes the spinal cord at the foramen magnum.

-Heart and respiratory rates.

-Origin of CN's IX-XII.

-Vasomotor center- smooth muscle tone of blood vessels.

-Autonomic center for:

.-Emesis: vomiting.

.-Deglutiton: swallowing. Coughing, hiccupping, and sneezing.

- 10% volume of brain and 50% of the brain's neurons.

-Arbor Vitae (tree of life)

-Coordination of movements and spatial reception.

-Balance and equilibrium.

-Time keeper, distinguishing pitch and similar sounding words, planing and scheduling tasks.

-Involves in our ability to speak.

-Patients with lesions in Broca's understand words, but cannot speak.

-Involved in understanding spoken and writen words.

-Patients with lesions in Wernicle's can speak, but words are nonsensible.

Occurs at approximately 90 min of sleep, after the fourth stage of NREM.

-Temporary paralysis: Skeletal muscles are actively inhibited, except the ocular muscles and the diaphragm.

-EEG, heart rate, respiratory rate, BP,and GI motility change.

-Deprevation of REM patient can become moody and depressed.

The storage and retrieval of information.

Two stages:

-Short Term Memory (STM)

-Long Tern Memory (LTM)

-AKA. Working memory.

-Temporary holding of information.

-Limit to 7 or 8 pieces of info.

Limitless capacity

-Specific information.

-Related to conscious thoughts and languages ability.

-Stored in the LTM with context in which learned.

-Less conscious or unconscious.

-Acquired through experience and repetition.

-Best remembered by doing. Hard to unclear.

-Includes:

Procedural memory

Motor memory

Emotional memory

-Basal nuclei relay to Thalamus and pre-motor cortex.

-Dopamine from Substantia Nigra needed.

-Skills: ex. Playing piano

-Amygdala.

-The hippocampus and surrounding temporal lobes function in consolidation and access of Memory.

-Acetylcholine needed for memory formation and retrieval.

-12 pairs of cranial nerves are associated with brain.

-Most are mixed nerves, but two pairs purely sensory

Sensory F / Motor F / PS* Fibers/

-Sensory nerve of smell

Yes (smell) / No / No

-Purely sensory (visual) function

Yes (vision) / No / No

-Raising eyelid, directing eyeball, constricting iris (parasympathetic), and controlling lens shape.

No / Yes / No

-Motor nerve that directs eyeball

No / Yes / No

-Three divisions: Ophthamic, Maxillary, Mandibular.

-Convey sensory impulses from various areas of face (V1 and V2).

-Supply motor fibers (V3) for mastication

Yes (general sensation) / Yes / No

-Motor, innervating lateral rectus muscle

No / Yes / No

-Motor: nerves of face. Facial expression.

-Sensory:(taste) from anterior two-thirds of tongue

Yes (taste) / Yes / Yes

-sensory function: hearing and balance;

Yes (hearing and balance) / Some / No

-Motor functions: tongue and pharynx for swallowing.

-Sensory functions: taste and general sensory impulses from pharynx and posterior tongue.

Yes (taste) / Yes / Yes

-Most motor fibers are parasympathetic fibers that help regulate activities of heart, lungs, and abdominal viscera.

-Sensory: taste buds of posterior tongue and pharynx

Yes (taste) / Yes / Yes

-innervate trapezius and sternocleidomastoid muscles

No / Yes / No

-Innervate extrinsic and intrinsic muscles of tongue that contribute to swallowing and speech

No / Yes / No