A&P Theory Unit 10 Notes PDF

**[A&P Unit 10 Notes ]** **[The Central Nervous System:]** - Consists of the brain and spinal cord - Functional Division Meninges: protective covering of the brain and spinal cord The meninges form the protective covering of the brain and spinal cord. It is comprised of three layers: - d...

**[A&P Unit 10 Notes ]** **[The Central Nervous System:]** - Consists of the brain and spinal cord - Functional Division Meninges: protective covering of the brain and spinal cord The meninges form the protective covering of the brain and spinal cord. It is comprised of three layers: - dura mater - arachnoid mater - pia mater. The spaces between these layers include: - epidural space - subdural space - subarachnoid space Cerebrospinal Fluid (CSF) - Cerebrospinal fluid circulates through the ventricles, or open spaces within the brain, and through the subarachnoid space.  **[Spinal Cord: ]** - The spinal cord connects directly to the brainstem. - The spinal cord is a continuation of the brain stem. It is a column of nerve tissue that runs from the base of the skull down the back. It is surrounded by three protective membranes and is enclosed within the vertebrae (back bones). **[Conus Medullaris:]** tapered ends, tip of spinal cord L1-L2 region **[Cauda Equina:]** "horse tail" run inferiorly to legs, provide motor control and sensation **[Filum Terminale:]** extension of pia mater, connects the spinal cord to the coccyx, stabilizes spinal cord.  White and Gray Matter: - White matter consists of axons and oligodendrocytes, while gray matter consists of neurons and unmyelinated fibers. White Matter: Saltatory conductions (Myelinated) Gray Matter: Continuous conduction (Unmyelinated) - Receptors detect stimuli and carry this information up the dorsal root into the dorsal horn of the spinal cord. Ascending tracts carry this information up to the brain. - The primary motor cortex of the brain initiates skeletal muscle movements. Motor commands are carried down the descending tracts of the spinal cord, out the ventral horn, and then down the ventral root to the muscles.   Ventral: Motor Dorsal Root: ganglion (cell bodies) Afferent, Sensory, Dorsal Efferent, motor, ventral Gray Matter: includes horns Gray matter: carries sensory and motor info, into and out of the spinal cord Polysynaptic Reflex Response: stimulus receptors ---\> sensory (afferent) ----\>internuron ----\> motor (efferent) ----\> effector **[Spinal Nerves: ]** In the human body there are 31 pairs of spinal nerves that are grouped into the corresponding regions of the spine. They gather sensory information and deliver motor commands to similar regions.  Cervical: head/neck, diaphragm deltoids, biceps, wrist extenders, triceps, hand (c1-c8) Thoracic: T1-T12, chest and abdominal muscles Lumbar: L1-L5, flex hip joint, leg muscles Sacrum: S1-S5, bowel/bladder, sexual function Coccyx: 31^st^, nerve (tail bone) **[Brain: ]** 4 Major areas of the brain - Cerebrum - Diencephalon - Brain Stem - Cerebellum Forebrain: higher learn Midbrain: reward mechanism Hindbrain: basic function Medulla Oblongata: controls basic functions, heart rate, blood pressure, etc. Pons: shuts off communication between body and brain, during sleep, respiration Cerebellum: "little brain" times events and coordinates it   The Cerebrum: - The cerebrum is divided into the left and right hemispheres along the longitudinal fissure. - Gyri and sulci (raised ridges and troughs) increase the surface area of the cerebrum.  **[Lobes:]** Lobes are sections of the brain. Each houses motor and sensory regions, including sensory cortices.   - Association areas receive complex information & direct complex motor reactions. Two important association areas are Wernicke's area and Broca's area.  **[Broca's Area:]** involved in speech production, written language, and sensorimotor functions **[Wernicke's Area:]** Involved in the comprehension of speech Broca Aphasia: type of aphasia, understating is good, finding words is difficult Wernicke\'s Aphasia: Type of aphasia, with poor comprehension, speech is effortless but meaning is impaired. **[Important Subcortical Areas of the Cerebrum: ]** **The Limbic System:** The limbic system is involved in emotion. Connects the hypothalamus to the frontal and temporal lobes, resulting in the physiological changes we experience as a part of intense emotion. **[The Diencephalon: ]** Diencephalon is located above the brain stem. It is made up of 3 parts: - epithalamus - thalamus - Hypothalamus  Thalamus: relays sensory information to the appropriate sensory cortex Hypothalamus: controls body tempo and other homeostatic mechanisms via the pituitary gland Epithalamus: regulates day and night cycles via the pineal gland (melatonin) and makes CSF The hypothalamus-pituitary complex is the command center of the endocrine system. **The Thalamus** - Serves as a relay station for most sensory and motor information. - Synapse point for neurons to carry information to/from the appropriate cortex.  **Epithalamus** The epithalamus regulates the body\'s day-night cycles through its connection to the pineal gland, which releases the hormone melatonin. **[The Brainstem: ]** The brainstem is made up of 3 parts: midbrain, pons, and medulla oblongata.  Midbrain: dopamine Pons: respiration, cranial nerves Medulla Oblongata: respiratory rate, cardiac function **[The Cerebellum: ]** - Responsible for physical balance while performing motor tasks. - Compares motor commands with sensory information - Alters rate & force of muscle reactions to accommodate for uneven ground, shifting position, & unexpected changes. - Ataxia is disturbances in balance. - The arbor vitae is located within the cerebellum which helps relay sensory and motor information to the cerebellum. It is composed of white matter that resembles tree branches   **[The Peripheral Nervous System:]** *All nervous tissue outside of the CNS.* Consists of the: - 12 Cranial Nerves - 31 Pairs of Spinal Nerves Some examples would be the nerves serving the digestive system, the glands, and the senses of seeing and hearing. The PNS communicates between the CNS and the rest of the body. **[Structural Divisions of the PNS]** The peripheral nervous system consists of cranial nerves and spinal nerves. - 12 cranial Nerves - 31 Spinal Nerves There are 12 pairs of cranial nerves that connect the brain to various parts of the human body. Cranial nerves will be classified in one of three categories based on their primary role: - Sensory - Motor - Mixed Each cranial nerve has a name that corresponds to its appearance or function. Each is also numbered using a dedicated Roman numeral.  1. Olfactory: smell 2. Optic: visual 3. Oculomotor: move eyeballs 4. Trochlear: superior oblique muscles of eye 5. Trigeminal: largest nerve, sensory info from head/face/ chewing 6. Abducens: innervates lateral l rectus muscle of eye 7. Facial Nerves: mixed nerves, control facial expressions 8. Vestibulocochlear: ear 9. Glossopharyngeal: mixed and senssoryt, tongue and pharynx 10. Vagus: mixed 11. Accessory 12. Hypoglossal  - **The spinal nerves have 4 major nerve plexuses: cervical plexus, brachial plexus, lumbar plexus, and sacral plexus.** Cervical: neck and diaphragm Brachial: pectoral girdles and upper limbs Lumbar/Sacral: innervate the pelvic girdle and lower limbs     **[Reflex Arc: ]** **[Anatomy of a Spinal Nerve :]** The 31 pairs of spinal nerves are mixed - meaning each spinal nerve carries both sensory & motor information. Dorsal root has a ganglion (bundle of nerves), ventral root does not Afferent: Carries info toward the brain Efferent carried down towards effectors **[Spinal Reflexes :]** Spinal reflexes are involuntary responses to a stimulus coordinated by the spinal cord. **[Reflex Arc:]** - Reflex arcs are neural pathways that are responsible for the automatic response between a sensory and motor neuron. - A sudden, rapid, and involuntary self-protective motor response? **[5 Component of a reflex arc:]** Receptor Sensory Neuron (Afferent) Interneuron (Integration/ Control Center) Motor Neuron (Efferent) Effector Polysynaptic: Have an interneuron, Monosynaptic: Do not require much communication, dont have interneuron Polysynaptic Reflex: - Used for more complicated tasks that require the coordination skills of an interneuron. - The interneurons are involved in mediating the reflex between the afferent (sensory) and efferent (motor) signals. **[Deep Tendon and Superficial Reflexes :]** Reflexes graded from 0-4 scale **[Babinski (Plantar Reflex)]** - Reflexes are automatic, but higher brain centers can influence or modify them. Interneurons and involved motor neurons are facilitated or inhibited. - The Babinski reflex is often used to test for neurological damage. It causes infants to fan the toes. - When descending inhibitory synapse develop, an adult will respond by curling the toes instead, called the plantar reflex. - Damage to the descending tracts of the spinal cord may revert the reflex to the infant response. **[Complete the Arc: ]** **[Parasympathetic and Sympathetic Nervous System:]** - Somatic nervous system do not utilize ganglion - Autonomic Nervous System use ganglion Sympathetic "fight or flight" (stress) (Long preganglionic neuron/short postganglionic) Parasympathetic "rest and digest" (peace) (Long postganglionic/ short preganglionic) Preganglionic neuron (first neuron) AcH released as neurontransmitter Postganglionic Neuron (second, neuron) Nictinic receptors Sympathetic: thoracic/lumbar Parasympathetic: cranial/sacral) AcH (pre and post ganglionic, muscrinic) Nicotinic: Muscarinic: Sympathetic Nervous System stimulates the Adrenal glands **[Neurotransmitter and Receptor Types:]** ======================================================= The PNS uses two Neurotransmitters: **[Acetylcholine: ]** Acetylcholine -- Activates cholinergic receptors Muscarinic acetylcholine receptors -- Can also be activated by muscarine (in poison mushrooms) Nicotinic acetylcholine receptors -- Can also be activated by nicotine (in cigarettes) **[Norepinephrine (noradrenaline):]** Norepinephrine (aka noradrenaline) - Activates adrenergic receptors Alpha 1 adrenergic receptors -- blood vessels, genitourinary system Alpha 2 adrenergic receptors -- pancreas and digestive system Beta 1 - located in the heart and kidneys Beta 2 - located in the lungs, blood vessels, GI tract, and other locations **[Chlorogenic: Acetylcholine (peace)]** **[Adrenergic: Noradrenaline (stress)]** **[Nicotinic: ]** **[Muscarinic: ]** **[Homeostatic Imbalances of the Nervous System ]** Palsy is an old term which refers to involuntary tremors and/or an inability to move. Bell's Palsy: an impermanent condition that causes sudden weakness in one side of the face. - Damage or inflammation of the facial nerve (CNVII) results in facial muscle weakness or paralysis. - Loss of forehead movement, facial drooping, drooping mouth Cerebral Palsy: Cerebral palsy is a permanent condition that leads to spastic muscles and uncontrollable movements. Caused by abnormal development of the brain or damage to the brain within the first year of life. A small number of cases are caused by oxygen deprivation. Stiff muscle, uncontrollable movement **[Progressive Degenerative Disorders:]** Alzheimer\'s disease is a progressive degenerative disorder in which plaques and tangles of protein fragments accumulate in the brain, interfering with normal brain function. This accumulation can lead to progressive **dementia, confusion**, and **memory loss.** **[Parkinson's Disease: ]** Parkinson\'s disease is a progressive degenerative disorder of the nervous system marked by tremor, muscular rigidity, and slow, imprecise movement, chiefly affecting middle-aged and elderly people. - Dopamine is required to send signals to motor neurons in the brain. - Dopamine is produced by the substantia nigra (\"the black substance\") of the midbrain. - Reduced dopamine levels leads to a plethora of nervous system symptoms. **[Huntington's Disease:]** Huntington\'s disease is an inherited condition that causes progressive degeneration of neurons in the brain. Signs and symptoms usually develop between ages 35 to 44 years and may include uncontrolled movements, loss of intellectual abilities, and various emotional and psychiatric problems. **[Demyelation Diseases:]**\ \ Demyelinating disorders occur when the myelin sheath surrounding neurons begins to break down, interfering with saltatory conduction of action potentials. - The majority of motor neurons are myelinated, as are many of the neurons in the brain, so this breakdown interferes with signals for muscle contraction and thought. **[Amyotrophic Lateral Sclerosis ]** Also known as ALS or Lou Gehrig\'s disease. A progressive neurodegenerative disorder in which motor neurons break down, leaving muscle cells to atrophy. Some demyelination is also seen with this disorder. Multiple Sclerosis An autoimmune disorder in which the immune system attacks myelin. Traumatic Injuries: **[Concussions:]**\ A concussion is a type of traumatic brain injury---or TBI---caused by a bump, blow, or jolt to the head or by a hit to the body that causes the head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in the brain and sometimes stretching and damaging brain cells. **[Hemorrhage:]** Hemorrhages are brain bleeds that can occur as a result of trauma, high blood pressure, or aneurysm (weakened blood vessels in the brain). As bleeding occurs, the intracranial pressure, or pressure within the skull, increases, which can cause further brain damage. **[Spinal Cord Injury:]** Damage to the tight bundle of cells and nerves that sends and receives signals from the brain to and from the rest of the body. A spinal cord injury (SCI) is damage to the tight bundle of cells and nerves that communicates between the brain and the rest of the body, carrying sensory and motor information. **[Incomplete Spinal Injury:]** An incomplete injury means the spinal cord is still able to transmit some messages to and from the brain to the rest of the body. **[Complete Injury:]** A complete injury means there is no nerve communication and motor function (voluntary movement) below the site where the trauma occurred. **Autonomic Dysreflexia:**\ Autonomic dysreflexia is life-threatening condition that occurs in patients with spinal cord damage who experience a urinary tract infection, bladder distention, or clogged Foley catheter. The autonomic nervous system overreacts to this stimulus, dangerously increasing blood pressure, while decreasing the heart rate. This initially presents as a throbbing headache. **[Strokes and Related Complications:]** A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or ruptures **Occlusive/Ischemic:** Occurs as the result of blockage or clot. **Hemorrhagic:** Occurs as the result of an aneurysm or burst vessel. **[Infection: ]** - Encephalitis is inflammation of the brain due to infection or inflammatory response. - One common cause of encephalitis is a viral infection spread by tick bites. **[Meningitis: (inflammation of 3 areas that protect brain and spinal cord) ]** Meningitis is an inflammation of the meninges. This usually results from a viral, bacterial, or fungal infection. Pia mater: innermost layer that touches brain and spinal cord Arachnoid: spider like middle layer Dura: Outermost, hardest layer **[Guillan-Barré]** Guillan-Barré (GBS) is a rare, autoimmune disorder in which a person\'s own immune system damages the nerves, causing muscle weakness and sometimes paralysis. - GBS can cause symptoms that last for a few weeks to several years. Most people recover fully, but some have permanent nerve damage. **[Seizures]**: **[Epilepsy:]** Epilepsy is a broad term used for a brain disorder that causes seizures. - There are many different types of epilepsy. There are also many different types of seizures. Seizures generally last between a few seconds and a few minutes. - Epilepsies cause sudden, uncontrolled electrical disturbances in the brain.