The Nervous System PDF

Central Nervous System (CNS) The Nervous System is divided in 2 The Autonomic Nervous System is ⬅️ Contains the Brain & Spinal Cord anatomical ways: subdivided into: Pe...

Central Nervous System (CNS) The Nervous System is divided in 2 The Autonomic Nervous System is ⬅️ Contains the Brain & Spinal Cord anatomical ways: subdivided into: Peripheral Nervous System (PNS) The rest of the body except the brain and 💙 💙 Peripheral Nervous System (PNS) Central Nervous System (CNS) Sympathetic Nervous System: (Fight or flight) Prepares the body for stressful spinal cord. _________________________________ _________________________________ ⭐ situations. ⭐ Dilate pupils _ _ ⭐ ⭐ Increase heartbeat 🇨🇴🇳🇹🇮🇳🇺🇦🇹🇮🇴🇳 ​ Relax airways The Peripheral Nervous System is subdivided in: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Of (PNS) subdivisions. ⭐ ⭐ Relax bladder Inhibit stomach activity 💙 Afferent _________________________________ _ ⭐ ⭐ Inhibit intestine activity Inhibit gallbladder Begins at the receptors. Carries sensory information from PNS to CNS. Contains sensory neurons. 💙Efferent ⭐ Inhibit salivation Secrete norepinephrine and epinephrine Transmits signals from CNS to muscles and glands. Somatic: Controls voluntary movements by innervating your skeletal muscles. Somatic Nervous System: Controls 🇮 ​🇳​🇭​🇮​🇧​🇮​🇹​: Means to restrain, Word of the Day #4 hinder, or prevent a process, action, or voluntary movements by innervating your 🇮🇳🇳🇪🇷🇻🇦🇹🇪 Word of the Day #1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​:Nerves connect skeletal muscles. activity from occurring. 🇸🇲🇴🇴🇹🇭 🇲🇺🇸🇨🇱🇪 to and send signals to parts of the body, Word of the Day #2 Parasympathetic Nervous System: like a muscle or an organ, helping it work ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​: (Rest and digest) Conserves the body’s or move. Involuntary muscle such as the stomach, energy. Visceral: Regulates involutary functions. intestines, blood vessels, and bladder. ⭐ ⭐Constrict pupils It innervates smooth muscles and glands. Autonomic Nervous System: Regulates _________________________________ Involuntary physiological functions. ⭐ ⭐ Stimulate saliva Slow heartbeat _ 🇵🇭🇾🇸🇮🇴🇱🇴🇬🇮🇨🇦🇱 Word of the Day #3 ⭐ ⭐ Constrict airways Stimulate activity of stomach ⭐ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​: Stimulate gallbladder ⭐Contract Processes and functions of living bladder organisms and their parts, focusing on Stimulate activity of intestines how biological systems operate and  interact to maintain life. Areas of the Brain The Autonomic Nervous System (ANS) Regulates the following: 💙 White matter: Mostly myelinated axons & ⭐Smooth ⭐Cardiac Muscles Oligodendrocytes. Signal transmission. High cont myelin. Summary of the Nervous System #1 PNS (Peripheral Nervous System) ⭐Glands Muscle (The Heart) _________________________________ 💙 Gray matter: Composed of cell bodies and dendrites. Processes Afferent (sensory) and Efferent (motor). _ information. ___________________________ SNS (Somatic Nervous System) Neurons: Nerve cells responsible for the _ transfer(send) and processing(read) of Controls voluntary muscle movements. information in the Nervous System. Types of Neuron Structures Visceral Neuroglia: Supporting cells that protect the neurons. Involuntary control of internal organs. _________________________________ _ ANS (Autonomic Nervous System) Neuroglia of the CNS (Central Nervous Divided into sympathetic (fight or flight) System) and parasympathetic (rest and digest). _________________________________ 💙 Astrocytes: Make up the blood brain barrier (BBB) It's the largest and most Anaxonic _ numerous. Found only in the CNS Neuroglia of the PNS (Peripheral Nervous System) 💙 Oligodendrocytes: Form Myelin sheath. 💙 Satellite Cells: Surround neuron cell bodies and provide support and nutrition. 💙 Microglia: Phagocytic cells. Engulf Regulate O2 and CO2, nutrients, and pathogens and debris. neurotransmitter levels around neurons in ganglia. 💙 Ependymal Cells: Produce cerebospinal fluid (CSF) 💙 Schwann Cells: Surround axons and produce Myelin sheath in the PNS (Peripheral Nervous System) Myelin is made of Phospolipids _________________________________ _________________________________ _ _ Bipolar Neuron 🇨🇴🇳🇹🇮🇳🇺🇦🇹🇮🇴🇳 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Of Types of Neuron Structures Anatomy of a Neuron Dendrites: Dendrites receive incoming signals from other neurons or sensory Axons are not myelinated _________________________________ receptors. They transmit these signals to Serial Neuron Pools _ the cell body, where the information is _________________________________ processed. _ Cell body: The cell body holds the Types of Neuron Functions nucleus and organelles, serving as the Sensory: Sends information from PNS to neuron's control center. It combines CNS. 💙💙 signals from dendrites and decides if it Two types: should send a signal down the axon. Somatic sensory neurons Visceral sensory neurons Axon: Conducts nerve impulse (action Motor: Sends information from the CNS potentials) toward axon terminals. to the PNS. Pseudounipolar Neuron Terminals: Affect another neuron or effector organ (muscle or gland) 💙💙 Two types: (SNS) Somatic motor neurons (ANS) Visceral motor neurons Long axons that split into two branches _________________________________ _ Interneuron: Involved in both (sensory 🇵🇴🇹🇦🇪🇨🇳🇹🇹🇮🇮🇴🇦🇳🇱 and motor) ​ ​ ​ ​ ​ ​ ​ Located entirely in the CNS (Central ​ ​ ​ ​ ​ ​ ​ ​ ​ ​#1 Nervous System) Processes sensory information and controls motor actions. The neuron is at rest, with a negative _________________________________ charge inside and positive charge outside.  When a signal is received, sodium _ 🇵🇴🇦🇹🇨🇪🇹🇳🇮🇹🇴🇮🇳🇦🇱 channels open, then sodium ions go into the cell. Making the inside more positive. ​ ​ ​ ​ ​ ​ ​ If the change in charge reaches a certain ​ ​ ​ ​ ​ ​ ​ ​ ​ ​#2 threshold. An action potential is triggered. The action potential travels along the axon. When reaching the axon 🇸🇵🇮🇳🇦🇱 🇨🇴🇷🇩 Each segment of the ​ ​ ​ ​ ​ ​ ​​ ​ ​ ​ ​ terminals, it releases neurotransmitters into the synapse. The neurotransmitters Consists of: bind to receptors on the other neurons' dendrites. Multipolar Neuron Dorsal roots: Composed of (afferent) Most common type in the CNS sensory neurons that bring signals from sensory receptors to the central nervous system (CNS) 🇷🇪🇫🇱🇪🇽🇪🇸 Classification of ​ ​ ​ ​ ​ ​ ​ ​ ​ 🇳​🇪🇵​🇺​🇴​🇷​🇴​🇴​🇱​🇳​🇸​🇦​ ​🇱​ Dorsal root ganglia: Contain cell bodies of sensory neurons. Somatic Reflexes: These reflexes involve the contraction of skeletal muscles. Divergence: Divergence occurs when Ventral roots: Composed of (efferent) Ex: The knee-jerk reflex one neuron sends signals to multiple motor neurons that send signals from the neurons. CNS to skeletal muscles and glands. Spinal Reflexes: Reflex actions that are processed directly in the Convergence: Convergence is when Ventral horn: The cell bodies of these spinal cord without involving the multiple neurons send signals to a single neurons are located in the ventral horn of brain. neuron. the spinal cord. Ex: The withdrawal reflex Serial Processing: In parallel Spinal nerve: Mixed nerves with both Cranial Reflexes: Reflexes that processing, a single input is processed efferent and afferent fibers. are processed by the brain rather simultaneously by multiple pathways. 🇸🇺🇲🇲🇦🇷🇾 ​ ​ ​ ​ ​ ​ ​ ​ The dorsal roots contain sensory neurons, than the spinal cord. Ex: The blink reflex Parallel Processing: Serial processing occurs when neurons transmit signals in a while the ventral roots contain motor Visceral (Autonomic) Reflexes: straight line, one after the other. neurons. Reflexes that are present at birth  and do not require prior Reverberation: Reverberation involves experience or learning. feedback loops where a signal is Ex: The baroreceptor reflex repeatedly sent through a circuit of neurons. Innate Reflexes: Reflexes that _________________________________ are present at birth and do not _ require prior experience or 🇨🇴🇳🇹🇮🇳🇺🇦🇹🇮🇴🇳 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ _________________________________ Brachial Plexus learning. Ex: The grasp reflex _ Acquired Reflexes: Reflexes that develop through experience and Molysypnatic: Reflexes that involve only learning. one synapse between the sensory and Ex: A trained athlete motor neurons. Sacral Plexus Polysypnatic: Reflexes that involve multiple synapses and may include interneurons. ​_________________________________ _ 🇵 ​🇱​🇪​🇽​🇺​🇸​🇪​🇸​ There are 4 _________________________________ _ Cervical Plexus Major Nerves Musculocutaneous Nerve Axillary Nerve Radial Nerve Median Nerve  Ulnar Nerve Lumbar Plexus Major Nerves Phrenic Nerve Major Nerves Lesser Occipital Sciatic Nerve Great Oricular Major Nerve Tibial Nerve Transverse Cervical Femoral Nerve Common Fibular Nerve Supraclavicular Nerves Obturator Nerve Pudental Nerve _________________________________ Lateral Femoral Cutaneous Nerve _ _________________________________ 🇸​🇮​🇬​🇳​🇦​🇱​🇸​ _ _________________________________ 🇨🇦🇺🇩🇦 🇪🇶🇺🇮🇳🇦 ​ ​ ​ ​ ​ ​​ ​ ​ ​ ​ ​ ​ _________________________________ _________________________________ _ _ _ ​ 💙 Afferent Signals The spinal cord typically ends at the 🇲🇼​🇦​🇭​🇹​🇮​🇹​🇹​🇪​🇪​🇷​​ ​ Entry: Signals enter the spinal cord lumbar vertebra L1 or L2 in adults. Below _________________________________ through the dorsal roots. this point, the remaining spinal nerves _ continue downward in a structure Afferent neurons (sensory neurons) have resembling a horse's tail, which is what Myelinated axons; transmits signals and their cell bodies located in the dorsal root "cauda equina" means in Latin. facilitates communication. ganglia. When sensory receptors (like _________________________________ those for touch, pain, or temperature) are _________________________________ _ activated, they generate signals that travel along these neurons to the spinal cord. 🇨🇴🇳🇹🇮🇳🇺🇦🇹🇮🇴🇳 _ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 🇬🇷🇦🇾 🇲🇦🇹🇹🇪🇷 ​ ​ ​ ​ ​​ ​ ​ ​ ​ ​ ​ 💙 Efferent Signals These signals exit the spinal cord through _________________________________ _ _________________________________ _ the ventral roots. Efferent neurons (motor neurons) have 💙 Vestibulospinal Tract Type: Descending tract (motor). Vestibular nuclei in the brainstem to spinal Neuronal cell bodies and dendrites; processes and integrates information. _________________________________ their cell bodies located in the ventral cord _ horn of the spinal cord. When the CNS decides to initiate a movement or response, it sends signals down these ⭐controlling Helps maintain balance and posture by extensor muscles in response 🇲🇪🇳🇮🇳🇬🇪🇸 ​ ​ ​ ​ ​ ​ ​ ​ ​ Protective layers of Brain & S.P Cord motor neurons to the target muscles or to changes in head position and _________________________________ glands. movement. It is involved in reflexive _ Summary adjustments to keep the body stable. Afferent: Sensory signals → Enter Superficial to Deep through dorsal roots → Carry information to the CNS. Efferent: Motor signals → Exit through _________________________________ _ 💙 Dura Mater: Outermost layer. & Toughest ventral roots → Carry commands from the CNS to the body. _________________________________ Ascending Tract Sensory (delivers information to the brain) Descending Tract 💙theArachnoid Mater: The middle layer of meninges, located between the dura _ Motor (delivers information to the mater and pia mater. It has a web-like 🇸🇵🇮🇳🇦🇱 🇨🇴🇷🇩 ​ ​ ​ ​ ​ ​ ​​ ​ ​ ​ ​ periphery) _________________________________ appearance.  🇹🇷🇦🇨🇹🇸 ​ ​ ​ ​ ​ ​ ​ _________________________________ _ 💙 Pia Mater: The innermost layer of the meninges, closely adhering to the surface _ Basal Nuclei #1 of the brain and spinal cord. 💙 ​ pinocerebellar Tract S Type: Ascending tract (sensory). The basal nuclei help fine-tune movements, ensuring they are smooth 💙 Subarachnoid Space: The space between the arachnoid mater Spinal cord to Cerebellum and coordinated. This includes adjusting and pia mater, filled with cerebrospinal ⭐Awarenessmovement of body position and both voluntary movements (like reaching for an object) and reflexive movements fluid (CSF). The fluid is absorbed and reused. (like pulling your hand back from something hot) Muscle memory. ⭐ Function: Cushions the brain and 💙Type:Spinal Spinothalamic Tract Ascending tract (sensory). cord to Thalamus Choroid Plexus spinal cord, providing protection against mechanical injury. The CSF also helps transport nutrients and remove waste. ⭐Carries pain, temperature, and crude touch sensations to the thalamus The choroid plexus is found within the ventricles of the brain. The primary _________________________________ _ function of the choroid plexus is to 💙Type: Corticospinal Tract Descending tract (motor). Cerebral cortex to spinal cord produce CSF, which cushions the brain, provides buoyancy, and helps transport nutrients and waste. Basal Nuclei #2 Much of the processing done by the basal ⭐of Responsible for voluntary motor control skeletal muscles. It sends signals from Nerve in the Sympathetic Nervous System that goes into the Adrenal nuclei occurs without conscious awareness. This allows the brain to automate routine movements and the brain to initiate and regulate Medulla responses, freeing up cognitive resources movement. for other tasks. The sympathetic preganglionic fiber _________________________________ that reaches the adrenal medulla is _ Basal Nuclei indeed unique because, unlike other Located near the Thalamus. sympathetic pathways, it does not Cerebral Aqueduct synapse in a traditional ganglion. Instead, it directly stimulates the Channel that connects the third and fourth chromaffin cells of the adrenal medulla, ventricle. The primary function of the which are specialized cells that function cerebral aqueduct is to allow the similarly to postganglionic neurons. When circulation of cerebrospinal fluid (CSF)  Astrocytes at the Pia mater activated, these cells release between the third ventricle (located in the epinephrine (adrenaline) and center of the brain) and the fourth Astrocytes have end-feet that extend to norepinephrine (noradrenaline) into the ventricle (located below the brainstem). blood vessels, anchoring themselves to bloodstream. the endothelial cells of capillaries. This Insula anchoring helps create the blood-brain Effectors ANS regulates barrier Smooth muscle The insula (or insular cortex) is a region Cardiac muscle of the brain located deep within the lateral ANS (Autonomic Nervous System) Glands sulcus (also known as the Sylvian fissure) Adipose tissue that separates the temporal lobe from the Pre- and postganglionic neurons are frontal and parietal lobes. part of the autonomic nervous system (ANS) Parasympathetic NS The insula is a critical brain region located Acetylcholine in both post and pre deep within the lateral sulcus that plays a Preganglionic neurons are the starting ganglionic neurons key role in processing internal bodily neurons that travel from the CNS to a Sympathetic NS sensations, emotions, taste, and ganglion, and postganglionic neurons Epinephrine and norepinephrine in post self-awareness. carry signals from the ganglion to the ganglionic neuron but Ach in body’s organs. preganglionic neuron. Sympathetic Chain Ganglia (Sympathetic NS) Preganglionic are in the CNS Next to spinal cord Short and synapses in a ganglion Cervical to sacral region Releases Acetylcholine Collateral Ganglia Postganglionic are in the PNS (Sympathetic NS) Long and extend to effectors (target Anterior to vertebral column organs) Near abdominal and pelvic arteries Releases Norepinephrine for Sympathetic Nervous System and Acetylcholine for Terminal (Intramural) Ganglia Parasympathetic Nervous System (Parasympathetic) Terminal: Near organs Intramural: Inside organs Ascending: From PNS to CNS (sensory) Adrenal Medulla Descending: From CNS to PNS (motor) (Sympathetic)  Adrenal glands Not a ganglia Epinephrine Ciliary Ganglia (Parasympathetic) Behind the eye Precentral Gyrus: Motor cortex Postcentral Gyrus: Sensory cortex