Kin 1060-Unit 2 PDF

2A.1- introduction to the nervous system Learning outcomes Describe the basic cells of the central and peripheral nervous system Differentiate between a typical motor versus sensory neuron Explain the role of myelin and define white matter versus gray matter Describe the structural f...

2A.1- introduction to the nervous system Learning outcomes Describe the basic cells of the central and peripheral nervous system Differentiate between a typical motor versus sensory neuron Explain the role of myelin and define white matter versus gray matter Describe the structural function differences between the central versus peripheral nervous systems, as well as the somatic versus autonomic nervous systems Nervous system The central nervous system is the main processing center and coordinator of all our body's functions The central nervous system includes the brain and spinal cord, whereas the peripheral nervous system includes all of the nerves that extend out into the periphery Cells of the nervous system Multipolar motor neuron Pseudounipolar sensory neuron The nervous system is comprised of different types of cells The two types of neuroglia Multipolar motor neuron Motor neurons send signals from the CNS to target organs Pseudounipolar sensory neuron All of our sensory fibers are and all the cell bodies of the pseudounipolar sensory neurons from the periphery are going to collect in ganglion. Neuroglia: myelination - Multiple sclerosis: is caused by the degradation of oligodendrocytes. Therefore the myelin is degrading around the axons White vs. grey matter Consider gray matter as the buildings in a city that process and store information, whereas white matter represents the roads, transit lines, and bike lanes that connect the buildings to transmit information. WHITE MATTER White matter primarily consists of myelinated axons, giving it a whitish appearance due to the lipid-rich myelin sheath. Its main function is to transmit signals between different regions of the CNS, facilitating communication and coordination. In contrast, gray matter contains neuronal cell bodies, dendrites, and unmyelinated axons, appearing grayish due to the absence of myelin and the presence of dense cell bodies. GREY MATTER Gray matter is primarily responsible for processing and integrating information, serving as the site of synaptic connections and neural activity. In the brain, white matter is found beneath the gray matter cortex, forming deeper structures, while in the spinal cord, white matter surrounds the central gray matter. Together, these two types of tissue enable the CNS to carry out its complex functions of communication, processing, and control. Myelinated and action potentials - Myelin plays a role in how fast signals are being sent along the neuron - Depolarization only happens at the nodes of ranvier Nervous system Peripheral nervous system -cranial nerves, ganglia, enteric plexuses, and sensory receptors Central nervous system- Brain and spinal cord Neuronal synapse Autonomic nervous system The autonomic nervous system (ANS) is a component of the peripheral nervous system (PNS) in charge of involuntary control of viscera (organs and glands) Parasympathetic signals come from cranial nerves and sacral spinal levels (craniosacral innervation), while sympathetic signals all come from spinal segments T1-L2 via the sympathetic chain/trunk Somatic nervous system - everything we can touch, feel and perceive The somatic nervous system is a component of the peripheral nervous system (PNS) in charge of voluntary motor control and peripheral sensation These motor and sensory components are spinal nerves associated with the level that they originate from, yielding patterned myotomes (motor) and dermatomes (sensory) Dermatomes and myotomes can be mapped to determine whether an injury is central or peripheral, and diagnose the level of injury (i.e. spinal level, brain region, nerve branch, etc) Functional overview  2A.1- Peripheral nervous system Learning outcomes Describe the basic anatomy of the brain and spinal cord Describe the anatomy of a spinal nerve and explain the distribution of sensory and motor neurons within it Explain the concept of a plexus and identify key areas of the spinal cord where the brachial plexus, sympathetic trunk, and lumbosacral plexus emerge Differentiate between the sympathetic and parasympathetic nervous systems and the general origins of their nerves Nervous system Functional overview The brain place on your head Cerebrum: The largest part of the brain, responsible for higher brain functions like reasoning, perception, and voluntary movement. It is divided into two hemispheres (left and right), each controlling the opposite side of the body. The cortex (outer layer) of the cerebrum is involved in complex cognitive functions, and it is folded into gyri and sulci to increase surface area. The cerebrum is also divided into lobes (frontal, parietal, temporal, and occipital), each responsible for different tasks like sensory processing, motor control, language, and vision. Cerebellum: Positioned at the back of the brain, beneath the cerebrum, the cerebellum is responsible for coordination, balance, and fine motor control. It helps maintain posture and ensures smooth and precise movement. Brainstem: The brainstem connects the brain to the spinal cord and controls vital autonomic functions such as breathing, heart rate, and blood pressure. It is divided into the midbrain, pons, and medulla oblongata. The brain stem also houses the reticular formation, which plays a crucial role in alertness and consciousness. -Frontal lobe: motor and higher order functioning, e.g. planning and reasoning -Temporal lobe: Auditory, smell, and memory processing -Occipital lobe: visual and visual processing -Parietal lobe: sensory and sensory integration Spinal cord The spinal cord terminates at the level of LII because of differential growth- our spinal cords stop growing early, but out bodies continue Spinal cord End of spinal cord- conus medularis The cauda equina is made up the spinal nerves that go to the lower lumbar, sacral, and coccygeal target areas that leave the spinal cord at its termination (around LII vertebral level) Spinal nerves Spinal cord meninges Spinal cord meninges: spaces Delivers anesthetic The lumbar puncture is very fast acting Spinal cord Spinal nerves - Anything distal to the spinal nerve is carrying both motor and sensory, whereas everything proximal is carrying either motor or sensory Spinal cord Plexuses and peripheral nerves Radial nerves: large nerve that supplies a vast number of muscles and sensory areas One dermatome can be supplied by many nerves The median nerve carries many spinal nerves Each of of the dermatome regions is supplied by a single spinal nerve Sympathetic trunk Autonomic nervous system Extra info: cranial nerves General somatic: Skeletal muscle, skin General visceral: Blood vessels, glands, intraocular muscles Special somatic: vision, hearing Special visceral: taste, smell - These do a range of functions mostly in the head and neck Preview: PSNS summary 2A.3- Autonomic nervous system Learning outcomes Define homeostasis and explain its role and importance in bodily function Describe the role of autonomic system in maintaining homeostasis and contrast it with the structure and function of the somatic system Differentiate between the functions of the sympathetic and parasympathetic nervous systems and describe their structural anatomy Consider the interface between somatic and autonomic systems. Can it be leveraged ? Quick little experiment Homeostasis is a neutral state that is maintained in the body for stability despite changing internal and external environments These processes are automatic and happen unconsciously to maintain a stable state in our body Homeostasis Autonomic nervous system Somatic vs. autonomic Somatic vs. autonomic neurons Autonomic nervous system  Impacts of autonomic system Sympathetic trunk Neurons ascend or descend the sympathetic trunk to carry sympathetic (fight, fight, or fright) signals through the periphery Sympathetic signals can only leave the trunk Sympathetic pathways Referred pain Autonomic pathways Extra info: cranial nerves Cranial nerves play crucial roles in sensory input (e.g., smell, vision), motor control (e.g., eye movement, facial expression), and autonomic regulation (e.g., heart rate, digestion). Each nerve has a specific function and pathway, making them vital for communication between the brain and body. While there are 12 cranial nerves in total, we will only focus on 4 BELOW Oculomotor Facial Glossopharyngeal Vagus Parasympathetic summary Autonomic summary