Presentation is loading. Please wait.

Presentation is loading. Please wait.

Neuro A&P Review. Nervous System CNS – Brain – Spinal cord PNS – Cranial Nerves – Spinal Nerves Afferent (sensory) pathways Efferent (effector/motor)

Similar presentations

Presentation on theme: "Neuro A&P Review. Nervous System CNS – Brain – Spinal cord PNS – Cranial Nerves – Spinal Nerves Afferent (sensory) pathways Efferent (effector/motor)"— Presentation transcript:

1 Neuro A&P Review

2 Nervous System CNS – Brain – Spinal cord PNS – Cranial Nerves – Spinal Nerves Afferent (sensory) pathways Efferent (effector/motor) pathways

3 Peripheral Nervous System Functionally – Somatic system – Autonomic system Sympathetic Parasympathetic

4 Nervous Tissue Neuron Supporting Cells – Astrocytes (multiple roles) – Oligodendria (form myelin in CNS) – Schwann cells (form myelin in PNS) – Microglia (CNS macrophage) – Ependymal (lines ventricles; forms CSF)

5 Neuron


7 Tracing the Neural Pathway Dendrite receives stimuli – Initiates depolarization at cell body – Electrical impulse jumps from node to node on axon – At end of axon, reaches axon terminal – Terminal releases neurotransmitters.

8 Initiation of Neural Impulse A single neuron may synapse with 50,000 other neurons – Each secretes a neurotransmitter or neuropeptide Hundreds of possible chemicals Some excitatory Some inhibitory Varying strength – Neuron must interpret this cacophony and decide... To depolarize or not to polarize... that is the question

9 Nerve Injury and Regeneration Axon is severed – Distal to injury Axon disintegrates Myelin sheath unwinds into Schwann cells and line path – Proximal Disintegration to the next node of Ranvier Cell body swells Begins to grow from stump of axon down Schwann path Limited by scar tissue

10 Brain Cerebral cortex (rind) – gray matter – Frontal – Parietal – Temporal – Occipital – Wernickes area – receptive aphasia – Brocas area – expressive aphasia

11 Brain Basal ganglia: motor function Thalamus: relay station Hypothalamus: HR, BP, sleep, etc. Cerebellum: motor coordination Brain stem – Midbrain – Pons – Medulla: respiration, heart, GI function, CN

12 Meninges 3 membranes surrounding brain and spinal cord – Dura mater – 2 layers Periosteum (next to cranium) (epidural space) Inner dura (meningeal layer) Subdural space between dura mater and next layer – Arachnoid membrane Follows contours of brain but not sulci Subarachnoid space between arachnoid and next layer – Pia Mater Delicate, follows sulci and fissures

13 CSF and Ventricles Similar to plasma Circulates in ventricles and subarachnoid space (125 – 150 ml) at any one time Brain floats in it – Cushions against jarring and jolting – Prevents pulling on meninges and blood vessels

14 Blood Supply Brain receives 20% of cardiac output Collateral circulation – Internal carotid – Vertebral arteries – Join in circle of Willis Venous drainage – Does not parallel arterial supply – Venous plexuses and dural sinuses drain into internal jugular vein

15 Neurotransmitters Multipurpose – Depends on post-synaptic neuron and receptor type Acetylcholine: multipurpose – Crosses neuromuscular junction of motor neurons – Released by both preganglionic sym & parasympa – Released by postganglionic parasympathetic fibers Cholinergic fibers

16 Neurotransmitters Norepinephrine – Released by posganglionic sympathetic fibers Adrenergic fibers – Released by adrenal glands Function of catecholamines varies by receptor and tissue of receptor – α1 receptor most common – α2 receptor cause inhibition/relaxation – β1 heart and kidney – β1 all other beta receptors

17 Functions of Autonomic System Generally – Sympathetic stimulation promotes protection of host Increase BP, HR, glucose Increase muscle blood flow and stimulation Decrease renal flow and digestion – Parasympathetic stimulation promotes rest, tranquility and maintenance functions Digestion Secretion of enzymes – Action is often antagonistic

18 Aging Extremely complex How much is aging, and how much is disease? Brain – Decreased weight and size – Increased adherence of dura mater to skull – Fibrosis of meninges – Widened sulci – Enlarged ventricles

19 Cellular Changes with Age Decrease in number of neurons – Not consistent with cognitive loss – Implications and reason are unknown Cellular changes – Dendrite changes – Lipofuscin deposition (Fatty deposits) – Neurofibrillary tangles (abnormal proteins) – Senile plaques (nerve degeneration) Last two are accelerated in Alzeimer's – Changes is neurotransmitter function

20 Tests of Nervous Function X-ray: primarily for bony structures CT: 2-D recreation from multiple X-rays – Structures, tumors, hemorrhage (with or without contrast) MRI: magnetic field; soft tissue analysis MRA (angiography): visualization of blood vessels (stroke and TIA) PET: injection of radioactive substances; detects positrons; indicates physiologic processes

21 Tests of Nervous Function Brain scan: uptake of radioactive isotopes Cerebral angiography Myelography: x-ray with subarachnoid dye Echoencephalography (ultrasound) Electroencephalography (EEG): seizures Evoked potentials CSF analysis: protein, blood, organisms

22 Spinal Cord Nerve cell bodies arranged in horns Nerve pathways cross in the spinal cord – Eg. Sensation of the left side of the body enters the left dorsal horn, and crosses to the right ventral horn and travels to right hemisphere Sensation – Spinothalamic tract: pain, temperature, crude and light touch – Posterior columms: does not cross sides; position, vibration, finely localized touch

Download ppt "Neuro A&P Review. Nervous System CNS – Brain – Spinal cord PNS – Cranial Nerves – Spinal Nerves Afferent (sensory) pathways Efferent (effector/motor)"

Similar presentations

Ads by Google