1 / 93

The Nervous System

The Nervous System. By: Kaylen Bunch & Kenzie Murphy. Major Structures. Central Nervous System (CNS): Brain & Spinal Cord Peripheral Nervous System (PNS): Network of nerves & Neural tissues Major Function: Sends signals threw the brain and spinal cord to the rest of the body. .

tabib
Télécharger la présentation

The Nervous System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Nervous System By: Kaylen Bunch & Kenzie Murphy

  2. Major Structures • Central Nervous System (CNS): • Brain & Spinal Cord • Peripheral Nervous System (PNS): • Network of nerves & Neural tissues • Major Function: Sends signals threw the brain and spinal cord to the rest of the body.

  3. Neurons • Specialized conductors of impulses that enable the body to interact with it's internal and external environments.

  4. Neurons • Neuroglia: supporting tissue • Axon: long slender projection of a nerve cell that conduct impulses away from the cell body. • Dendrites: Are short & unsheathed, & transmit impulses to the cell body.

  5. Neurons

  6. Neurons • Motor Neurons: Contractions in muscles & secretions from glands & organs. • Sensory Neurons: Attached to sensory receptors & transmit impulses to CNS. • Interneurons: Mediate impulses between sensory & motor neurons.

  7. Nerve Fibers • A single elongated process. • PNS fibers: Wrapped by sheaths containing Schwann cells, so damage is reversible, • CNS fibers: No Schwann cells, so permanent damage.

  8. Nerves: a bundle of nerve fibers that connect to various parts of the body • Afferent: Conducting to the CNS • Efferent: Conducting to muscles, organs, & glands. • Mixed: Mixture of afferent and efferent.

  9. Nerve Impulse • All or None Principle: No transmission occurs until the stimulus reaches a minimum strength then a maximum impulse is produced. • Synapse: A specialized knoblike branch ending. • Neurotransmitter: chemical agent helper.

  10. Central Nervous System (CNS)

  11. CNS: Central Nervous System • Brain and Spinal Cord • Divided into white and gray matter. • Spinal Cord’s gray matter is in a “H” shape.

  12. Brain • The nervous tissue consists of millions of nerve cells & fibers • Male- 1380g. or 3.04lbs. • Female- 1250g. or 2.75lbs. • Function: • Receives information from the body • Interprets it • Gives a response to it • Helps perform vital operations

  13. Brain (Meninges) • 3 membranes that enclose the brain. • Meninges support blood vessels and contain cerebrospinal fluid. • Pia mater - inner layer • Arachnoid – middle layer • Dura mater – outer layer

  14. Cerebrum • Description: Divided by the longitudinal fissure into 2 cerebral hemispheres. • Function: Contains nerve centers that govern all sensory and motor activity. • They are joined by large fiber tracts that allow information to pass between them.

  15. Left Right

  16. Cerebrum • The surface of each hemisphere is arranged in folds creating bulges(convolution) & shallow furrows( sulcus). • Cerebral Cortex: The surface of each hemisphere, composed of gray, unmyelinated cell bodies. • Divided into lobes to identify certain locations.

  17. Cerebrum Lobes • Frontal: Major motor area, site for personality, & speech. • Parietal: Contains centers for sensory input from all parts of the body & is the site for the interpretation of language. • Temporal: Contains centers for hearing, smell, & language input. • Occipital: Primary sensory area for vision.

  18. Cerebellum • Occupies a place in the back of the skull, is oval shaped & divided into lobes by deep fissures. Is also connected to every part of the CNS. • Function: Coordination of voluntary & involuntary complex patterns of movement & adjusts muscles to automatically maintain posture.

  19. Cerebellum

  20. Diencephalon • Thalamus: Relay center for all sensory & motor impulses being transmitted to the sensory & motor areas. • Hypothalamus: Regulates autonomic nervous activity & contains neurosecretions used to control metabolic activities.

  21. Brainstem • Contains centers that process visual, auditory, & sensory data & relay information to & from the cerebrum. • Midbrain: below cerebrum & above pons. • Contains 4 small masses of grey cells that are associated with visual reflexes & sense of hearing.

  22. Brainstem • Pons: broad band of white matter • Contains fiber tracts linking the cerebellum & medulla to higher cortical areas. • Plays a role in somatic & visceral motor control.

  23. Brainstem • Medulla Oblongata: Connects the pons & the rest of the brain to the spinal cord. • Acts as the cardiac, respiratory, & vasomotor control centers. • Controls • Breathing • Swallowing • Coughing • Sneezing • Vomiting • Heartbeat • Arterial blood pressure

  24. Spinal Cord • Adult cord is about 44 cm. long. • Function: • Conduct sensory impulses to the brain • Conduct motor impulses from the brain • Reflex center for impulses entering & leaving spinal cord without involvement of the brain.

  25. Spinal Cord • Conus Medullaris: Between 12th thoracic & 1st lumbar vertebra. The cord becomes conically tapered. • Filum Terminale: terminal thread of fibrous tissue extends from the conus medullaris to 2nd sacral vertebra.

  26. Spinal Cord • Cauda Equina: (horses tail) terminal portion that forms the nerve fibers that are the lumbar, sacral, & coccygeal spinal nerves.

  27. Cerebrospinal Fluid • Colorless fluid produced by the choroid plexuses within the ventricles of the brain. • Circulates through the ventricles, central canal, & subarachnoid space. Is removed by the arachnoid villi. • Adult 120 – 150mL. • Cushions the brain & spinal cord from shocks that could cause injury.

  28. PNS: Peripheral Nervous System Central Nervous System • Network of nerves branching throughout the body from the brain & spinal cord. • 12 pairs of cranial nerves attach to the brain. • 31 pairs of spinal nerves connected to the spinal cord. Peripheral Nervous System

  29. Cranial Nerves • Attached to the brain. Arranged symmetrically, 12 to each side of the brain. • Function: Provide sensory input, motor control, or a combination of these functions.

  30. Spinal Nerves • 31 pairs along the length of the spinal cord & from the vertebral canal. • Each nerve is divided into 2 roots. • Dorsal/Sensory roots: composed of afferent fibers carrying impulses to the cord • Ventral Roots: contain motor fibers carrying efferent impulses to muscles & organs

  31. Spinal Nerves • Cervical: 8 pairs • Thoracic: 12 pairs • Lumbar: 5 pairs • Sacral: 5 pairs • Coccygeal: 1 pair

  32. ANS: Autonomic Nervous System • A part of the PNS. • Controls involuntary bodily functions: • Sweating • Secretion of glands • Heart • Arterial blood pressure • Smooth muscle tissue

  33. ANS: Autonomic Nervous System • Composed of efferent fibers from certain cranial & spinal nerves that are divided into the: • Sympathetic Division • Parasympathetic Division • The 2 divisions counteract each other to keep the body in a state of homeostasis.

  34. Sympathetic Division • Since sympathetic fibers synapse with cell bodies in the sympathetic ganglia, they produce widespread innervation when activated. • This is called the fight-or-flight response. • This division also causes the release of epinephrine (adrenaline), causing an adrenaline rush.

  35. Fight-or-Flight Response • During this a person experiences:

  36. Parasympathetic Division • Works to conserve energy and innervate the digestive system. • When activated it: • Stimulates salivary & digestive gland • Decreases metabolic rate • Slows heart rate • Reduces blood pressure • Allows material through intestines & absorption of nutrients by blood

  37. Alzheimer’s Disease (AD) • Loss of memory & other cognitive functions. • Involves the parts of the brain that control thought, memory,& language. • Begins after age 60, and risk goes up with age. • Not a normal part of aging.

More Related