Bio 255 Exam 3 Questions and Answers

Bio 255 Exam 3 Questions and Answers collect info, process info, respond to stimuli nervous tissue functions: afferent sends info to CNS efferent sends info away from CNS afferent The sensory nervous system is ________________________. efferent The motor nervous system is ________________________. somatic sensory NS part of sensory NS; voluntary; touch, pain, pressure, vibration, proprioception visceral sensory NS part of sensory NS; involuntary; impulses from visceral blood vessels somatic motor NS voluntary; impulses from CNS causing contraction of skeletal muscles autonomic motor NS involuntary; impulses from CNS regulate smooth/cardiac muscles neurons electrically excitable cells that initiate, transmit, and receive nerve impulses glial cells support/protect neurons smaller, more Glial cells are ____________________ and ____________ numerous than neurons. neurons basic structural unit of the NS metabolic rate, longevity Neurons have high ___________________ and extreme ___________________. 6 Neurons are nonmitotic after _____________ months. dendrites take in nerve signals and send to cell body cell body has nucleus, nucleolus, mitochondria, ribosomes, RER of neurons axon transmit nerve impulses away from cell body and to other cells axon hillock region where cell body connects to axon axon collaterals side branches of main axon telodendria terminal extensions at the end of axon and it's collaterals synaptic knobs tip of telondendria that secretes neurotransmitter multipolar Motor neurons are _____________________. (uni, bi, or multipolar) interneurons facilitate communication between sensory and motor neurons CNS Interneurons are only in the ____________. interneurons 99% of neurons in the body are ___________________. sensory to motor; between interneurons How do interneurons carry impulses? astrocytes glial cells that maintain blood-brain barrier astrocytes most abundant glial cells astrocytes glial cells that perform CNS repair by forming a glial scar astrocytes glial cells that assist neural development ependymal cells glial cells that form choroid plexus with capillaries and produce CSF ependymal cells glial cells that line ventricles of brain and central canal of SC microglial cells glial cells that phagocyte cellular debris from dead or dying tissue microglial cells glial cells that derive from bone marrow oligodendrocytes glial cells that produce myelin (insulator of electrical activity) oligodendrocytes glial cells that are associated with CNS axons (wrap around axons) astrocytes, ependymal cells, microglial cells, oligodendrocytes glial cells in CNS satellite cells, neurolemmocytes glial cells in PNS satellite cells glial cells that protect cell body and regulate nutrients neurolemmocytes glial cells that produce myelin in PNS neurolemmocytes also known as Schwann cells nodes of Ranvier between adjacent insulating cells saltatory conduction electrical signals jump from node to node, so travels down axon more quickly fiber size, pressure of myelin Increasing ___________________ and __________________ increases the transport speed of axons. gray mater unmyelinated fibers and cell bodies white mater myelinated fibers and cell bodies scar tissue Astrocytes form ___________________ in pathway of axons physically preventing regeneration. permanent Injury to CNS is usually _______________, but not always PNS Where does axon regeneration occur? nerves bundles of afferent and efferent fibers (axons) and PNS (outside of CNS) endoneurium wraps around each individual axon perineurium wraps around fascicles epineurium wraps around entire nerve tracts bundles of afferent and efferent fibers (axons) within CNS synapses specialized junction between an axon and another neuron electrical synapse occurs between gap junctions of tightly connected cells chemical synapse signal causes the release of a neurotransmitter into the synaptic cleft OK Read neural transmission at a chemical synapse page 4 of notes ectoderm Nerve tissue is derived form ________________. CNS Neural tube comes from _____________. bone, meninges, CSF physical protection of CNS blood-brain barrier chemical protection of CNS neurocranium encloses brain vertebra encloses spinal cord protect CNS, protect blood vessels, contain CSF, form partitions with skull functions of meninges dura mater superficial meningeal layer dural septa limit brain movement dural sinuses drain blood from the brain arachnoid mater middle meningeal layer subdural space separates dura mater from arachnoid mater subarachnoid space beneath arachnoid, filled with CSF and blood vessels arachnoid villi allow CSF to be absorbed by venous return pia mater adheres to surface of brain/spinal cord pia mater takes out waste and nourishes brain CSF nourishes brain and carries chemical signals throughout it ependymal cells, choroid plexus CSF is formed from blood by ______________________ and ____________________ in brain ventricles. ventricles cavities within the brain blood-brain barrier selective barrier made by epithelial tight junctions of capillaries and astrocytes denticulate ligaments attach spinal cord to dura mater pia mater Where are denticulate ligaments made? epidural space around meninges within spinal cord filled with fat, CT, blood vessels reflexes quickest reactions to stimulus conus medullaris structure where SC ends cauda equina group of axons inferior to conus medullaris filum terminale pia mater that anchors conus medullaris to coccyx cervical enlargement innervates upper limbs lumbosacral enlargement innervates lower limbs anterior median fissure deep, wide groove on ventral side