BIO 446L 1st Edition Lecture 14 Outline of Last Lecture I. Nervous Tissue contda. Peripheral nervous systemi. Organizationii. Small nerves and gangliaiii. Glial cellsiv. RegenerationII. Nerve Pathways in the CNS and PNSa. Motor pathwaysb. Indirect motor pathwaysOutline of Current Lecture I. Spinal Cord Injurya. ParalysisII. Somatic sensory pathwaysa. PNSCNSb. Sensory pathwaysc. Spinal nerve reflexIII. Autonomic Nervous Systema. Cranialb. Organizationi. Sympatheticii. Parasympatheticc. Sympathetici. Thoracolumbard. Parasympathetici. craniosacralCurrent LectureSpinal Cord Injury- paralysiso cervical—quadriplegiao thoracic—paraplegia(waist down)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o sacral—paraplegia (hips down)Somatic Sensory Pathways- pathway begins in PNS and projects to CNS- initiates in sensory nerve endings o when stimulated, an action potential fires- sensory gangliao afferent and efferent sensory axons- sensory pathwayo three neurons in series nerve endings—cross over gray matter in spine up spine to thalamus—spinothalamic primary cerebral cortexo left sided info goes to the left side of the brain here (and vice versa)o dorsal pathways deep vibrations, proprioseption (knowing where a body part is/awarenessof that body part’s position and location)o spinocerebral pathway no conscious perception muscle spindles dorsal gray matter white matter pons cerebellum balance, purposeful movement (correcting a step, not over-reaching or under-reaching for an object)o sensory pathways post central gyrus= primary sensory cortex lips and skin of face are very sensitiveo spinal nerve reflex (stretch reflex) aka knee jerk reflex muscle spindle—heavily innervated- when entire muscle is stretched, response is mediated by muscle spindle- sensory neuron endings dorsal root ganglia posterior gray matter anterior gray matter with motor neuron neuromuscular junction at quad contraction- secondary branch to brain that mediates the consciouso you are aware that you have kicked your legAutonomic Nervous System- cranialo afferent and efferent neuronso bundles of axons (including parasympathetic neurons)o no sympathetic in braino know the cranial nerves- organizationo innervate cardiac muscles, smooth muscle, and glandso divisions sympathetic (thoracolumbar)- lateral cell columns- pre ganglionic cell bodies in thoracic and upper lumbar parasympathetic (craniosacral)o pre-ganglionic= cell bodies in CNS myalinatedo post-ganglionic= cell bodies in autonomic ganglion cranial, spinal, or discrete nerves Nonmyalinated- Sympathetic divisiono Thoracolumbaro Not always excitatory, but typically a flight or fight response Think of fight or flight when thinking of physiological effects- Pupil dilation, increased heart rate, blood flow to muscles, blood flow away from digestive system, etc.)o Pre-ganglionic sympathetic cell bodies in lateral horno Chain of sympathetic ganglion along vertebral columno Pre ganglionic axon is short and post is long Post is nonmyalinated and slowero Pre ganglionic neurons secrete acetylcholine (nicotinic receptors—ligand gated sodium channel)o Post ganglionic neurons secrete norepinephrine (adrenergic receptor—also ligand gated)o Effect of these receptors depend on the tissue typeo Thoracolumbar bones As you move down the spine, correlate to body parts from the head downo Sympathetic pathway to adrenal medulla Inside of adrenal gland Pre ganglionic axon out of spinal cord peri vertebral ganglionprevertebtal ganglion cells in adrenal medulla secretes Ach nicotinic receptoro No neuromuscular junction in sympathetic SNS terminal (periarterial plexus) Axon extends to target tissue and branches spread with varicosities (beads) of neurotransmitter- Target is bathed in neurotransmitter- Parasympathetic o Craniosacralo Pre ganglionic in brain stem, medulla Very long, myalinatedo Post ganglion are short Right on tissue,
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