Presentation on theme: "Nervous System By: Joe Matten Casey Crocamo Kevin Li Allie Erickson Wenyi Lau."— Presentation transcript:
Nervous System By: Joe Matten Casey Crocamo Kevin Li Allie Erickson Wenyi Lau
Nervous System Neurons can help to take in stimuli from both outside and inside the body. They can process these stimuli to control other bodily functions.(motor output) The three types of neurons are sensory(afferent), interneurons, and motor(efferent) A good way to remember the difference is efferent=effect
Nervous System(CNS+PNS) The nervous system is separated into two parts, peripheral and central. The central includes the brain and the spinal cord. The peripheral includes all of the nerves outside of the brain and spinal cord
PNS PNS is separated into the somatic (voluntary) and autonomic (involuntary) systems.
Types of nervous system cells Astrocytes, microglia, ependymal, oligodendrocytes, satellite, schwann. Astrocytes are starshaped, they form the barrier between the capillaries and neurons in the brain. Microglia are spider-like phagocytes that collect trash. Ependymal cells line the brain+spinal cord spaces. They help move CSF.
Nervous system cells Oligodendrocytes produce myelin sheath around nerve fibers in the CNS Satellite cells protect neurons Schwann cells produce myelin sheath around the nerve fibers in the PNS
Cell Body Nissl substance is the specialized rough ER Neurofibrils provide a cytoskeleton that helps cells maintain their shape
Neurons Dendrites conduct impulses towards the body, while Axons take them away from the body. There are axon terminals with vesicles and neurotransmitters. They are separated with a synaptic cleft. Schwann cells produce myelin sheaths. The gaps between these schwann cells are called the Nodes of Ranvier.
Cell bodies Gray matter consists of cell bodies and unmylenated fibers. Nuclei are clusters of cell bodies within the white matter.
Cell bodies Multipolar neurons have multiple extensions from the body Bipolar neurons have one axon and one dendrite Unipolar neurons have a short single process leaving the cell body.
Neurons The plasma membrane is polarized at -70mv There are more sodium ions outside of the membrane, with more potassium ions inside the membrane. Threshold is at -55mv. It depolarizes, Na+ channels open to let sodium ions flow in. It then repolarizes, the potassium channels opens and the potassium ions are sent in.
Neurons It then hyperpolarizes for a few milliseconds and enters the refractory period where it cannot transmit any signals
Reflex Arc The reflex arc is the route from a sensory neuron to an interneuron then to an effector. There are two types of reflex arcs, autonomic and somatic. Autonomic reflexes include smooth muscle regulation, heart+blood pressure regulations, glandular regulation and digestive system regulations. The somatic reflexes include activation of skeletal muscles
CNS The CNS develops from the embryonic neural tube, includes the brain and the spinal cord. There are four chambers in the brain filled with CSF. There are 4 main regions of the brain, the cerebral hemispheres, diencephalon, brain stem and cerebellum. There cerebrum has a frontal, parietal, occipital and temporal lobe.
Lobes of The Brain Frontal Lobe Parietal Lobe Occipital Lobe Temporal Lobe
Cerebrum The cerebrum consists of an outer layer made up of gray matter. The cerebral cortex is involved in speech, memory, logical and emotional responses, consciousness, interpretation of sensation, and voluntary movement
White Matter Corpus Callosum connects the hemispheres of the brain.
Diencephalon Made of three parts: Thalamus Hypothalamus Epithalamus
Diencephalon Thalamus: relays sensory impulses Hypothalamus: helps to regulate body temperature, controls water balance and regulates metabolism Part of limbic system Epithalamus: includes pineal gland and the choroid plexus (forms CSF)
Brain Stem Midbrain: reflex centers for vision and hearing Pons: control of breathing Medulla oblongata: heart rate control, blood pressure regulation, breathing, swallowing and vomiting
Reticular Formation Involved in sleep/wake cycles and consciousness Also involved in motor control of visceral organs
Cerebellum coordination of body movements The central nervous system is protected by the scalp, skin, skull, cerebrospinal fluid, blood brain barrier and vertebral column and the meninges
Meninges Dura mater: exterior cover and contains periosoteum and meningeal layer Arachnoid layer: middle layer and is web-like Pia mater: the internal layer and clings to the surface of the brain
Cerebrospinal Fluid Formed by the choroid plexus and protects and cushions the brain Found inside the arachnoid space
Blood Brain Barrier Protects the brain from harmful substances The things that can pass through: Fats and fat soluble molecules Respiratory gases Alcohol Nicotine Anesthesia
Traumatic Brain Injuries Concussion: slight brain injury and leads to no permanent brain damage Contusion Nervous tissue destruction occurs Nervous tissue does not regenerate Cerebral edema Swelling from the inflammatory response May compress and kill brain tissue ; 3 ;
Stroke Cerebrovascular Accident (CVA) Caused by a ruptured blood vessel and results in oxygen deprivation
Alzheimer’s disease This is when victims experience memory loss, irritability, confusion, and hallucinations and eventually death
Spinal Cord Carries nerve impulses from the brain to the limb Protected and cushioned by the meninges
Peripheral Nervous System
Structure of a Nerve Outer: endoneurium Middle: perineurium Inner: epineurium