UNIT 5 REVIEW GUIDE - NERVOUS SYSTEM 1a) State the 3 functions of the nervous system. 1: sensory 2: integration 3: motor output 1b) Complete a flow chart showing the relationships within the nervous system using the following terms: Central nervous system, autonomic nervous system, peripheral nervous system, parasympathetic, and sympathetic nervous system 2) Sketch a typical NEURON in the space below. Label the following structures: cell body dendrites axon nodes of Ranvier neurotransmitters nucleus myelin synaptic end bulb vesicles direction of impulse glial cell 3) How are neurons different than neuroglial cells? neurons transmit information/messages with action potentials; neuroglial cells support neurons but do not actually pass the electrical message 4) State the function of each of the following neuroglial cell types: oligodendrocytes: makes myelin in the CNS astrocytes: functions as support as in the blood brain barrier Schwann cells: makes myelin in the PNS
5a) What is the purpose of MYELIN (i.e. the MYELIN SHEATH)? Insulation; keep electrical charge/depolarization inside axon 5b) Describe axon myelination & its role in saltatory conduction. Because there is a layer of lipid insulation wrapped around the axon, depolarization can travel through the axon until the Node of Ranvier. At the Node, there is another set of sodium/potassium channels. Since the depolarization travels to this point, it can open this sodium channel & begin a new action potential. These nodes are separated by space so it appears as if the action potential is jumping down the axon. 6) Describe the general function(s) of each of the following neuron types: I) SENSORY NEURONS: detect a stimulus II) INTERNEURONS: processing; integration III) MOTOR NEURONS: send message to effector (muscle cell, gland cell) 7a) List & briefly describe the four events that occur to create an ACTION POTENTIAL. 1) Resting potential: neuron cell is at approximately -70 mv. Na & K gates are both closed 2) Depolarization: stimulus increase the membrane potential to -55mV and as a result, has crossed the thresh hold to fire an action potential; Na gates open and Na rushes into the cell; cell becomes more positive on the inside 3) Repolarization: Na gate closes & K gate opens; K moves out of the cell and this decreases the membrane potential inside the cell (it becomes more negative) 4) Undershoot: K gate is slow to close so too much K leaves the cell (Na gate still closed); cell becomes even more negative **Refractory time period: time between action potentials when the Na/K pump resets the ion concentrations (Na pumped back out & K pumped back in; uses ATP) 7b) Draw and label a graph of the four phases of an action potential. 7c) How does the neuron return to its resting state (membrane potential)? Sodium-potassium pump 8a) What is the resting potential of a neuron and what is the threshold potential? Resting: -70mV Threshold: -55mV 8b) What is meant by an all-or-none response? An action potential is either going to fire or not fire; if the membrane potential reaches -55mV, an action potential WILL occur
8c) How is a stimulus of greater intensity processed as compared to a stimulus of lesser intensity: more stimulus leads to a greater frequency (number) of action potentials 9a) List the events that occur at a SYNAPSE when an impulse is transmitted from neuron to another. Depolarization reaches the synaptic bulb (aka axon end terminal bulb) and this causes the vesicles to fuse with the neuron s membrane; neurotransmitter then spills into the synapse; neurotransmitter diffuse across the synaptic cleft & binds to the appropriate receptor in the post-synaptic cell s membrane; this initiates a new action potential in the next neuron 10a) What is a NEUROTRANSMITTER? A chemical messenger 10b) List the neurotransmitters in the human body from your notes & their function. 1) ACh: stimulates skeletal muscle contractions 2) dopamine/serotonin: affect sleep, mood, attention, learning 3) endorphins: decrease the perception of pain 4) epinephrine/norepinephrine: attention & mental focus, cognition 5) histamine: released in hypothalamus promotes alertness 11a) Draw the following information: there are synaptic end bulbs from 2 different neurons synapsing with the dendrites of a 3 rd neuron which is at rest. Synaptic end bulb #1 releases neurotransmitters that cause a -5 mv change inside the cell body and synaptic end bulb #2 releases neurotransmitters that cause a +25mV change inside the cell body. 11b) Will there be an action potential generated in neuron #3? YES! How do you know? Charge is -50mV; crossed threshold 12) What is a REFLEX? Involuntary/automatic response
13) List the 5 steps/actions that occur during the knee-jerk reflex and the pupillary reflex. KNEE-JERK: Activate stretch receptors in the quad muscle (when doctor hits patellar tendon with hammer ) Sensory neurons relay message to spinal cord Interneurons in spinal cord process this information & send message to motor neurons to make a correction Motor neurons take message back to quad muscles Quad muscles (effector) contract causing the leg/tibia to jerk up PUPILLARY: Activate light receptors in the eye (when doctor shines light into 1 eye) Sensory neurons relay message to brain stem Interneurons in brain stem process this information & send message to motor neurons to make a correction Motor neurons take message back to muscles controlling pupil size Muscles controlling pupil size (effector) in BOTH eyes contract causing pupils to constrict & become smaller 14a) List the four major regions of the brain & their general function: CEREBRUM: thinking; personality; memory; main integration CEREBELLUM: coordinates where your body is in space & time; major muscular coordination BRAIN STEM: vital reflexes for homeostasis (coughing, sneezing, vomiting, breathing) DIENCEPHALON: homeostasis (hunger, thirst, body temp), biological clock, relay center 14b) Differentiate between the function of the motor cortex & somatosensory cortex. Which brain region are these found in? Both are found in the cerebrum; somatosensory cortex receives sensory information (such as pressure, touch, pain, temperature) to be processed. The motor cortex sends commands to skeletal muscles 15a) State the location of the CORPUS CALLOSUM. Joins left & right hemispheres of the brain 15b) What is its function? Help integrate information from right & left sides of the body 16) Describe the location AND functions of CEREBROSPINAL FLUID. > Location: around the brain & spinal cord > Functions: cushion, protect, nourish
17) On the diagram below, label the: -occipital lobe -CEREBELLUM -hypothalamus -midbrain -frontal lobe -medulla oblongata -corpus callosum -thalamus -parietal lobe -pons -pituitary gland -spinal cord -temporal lobe FRONTAL LOBE PARIETAL LOBE CORPUS COLLOSUM HYPOTHALAMUS PITUITARY TEMPORAL LOBE OCCIPITAL LOBE THALAMUS MID BRAIN PONS CEREBELLUM MEDULLA OBLONGATA SPINAL CORD 18) Complete the following chart of the various parts of the brain: Region / Structure Where in the brain? Function(s) Thalamus diencephalon relay center that sorts out & transmits sensory information to and from cerebrum Hypothalamus diencephalon controls many important brain activities, most involved with homeostasis; ex: control ANS, body temperature, pituitary gland and production of hormones, regulates emotional (such as feelings of rage, aggression, pain, and pleasure) and behavioral patterns such as those related to sexual arousal; regulates eating and drinking; regulates circadian rhythms Pineal Gland diencephalon secretes melatonin which promotes sleepiness and contributes to setting the body s biological clock Optic chiasma diencephalon Region where the right and left optic nerves cross each other before entering the brain; this allows objects from each visual field to be processed together (also gives depth perception) Midbrain Brain stem receives and sends sensory information that coordinates eye movements/head movements to respond to stimuli Pons Brain stem regulates breathing centers in the medulla oblongata
Region / Structure Where in the brain? Function(s) Medulla oblongata Brain stem Considered the most vital part of the entire brain for keeping us alive! controls involuntary reflexes like breathing, heart and blood vessel activity, swallowing, vomiting, sneezing, digestion Frontal lobe cerebrum Reasoning; planning; emotions; problem solving; part of the speech process; movement Parietal lobe cerebrum Movement; orientation; perception of sensory stimuli Temporal lobe cerebrum Perception & recognition of auditory stimuli; memory; speech Occipital lobe cerebrum Visual processing Cerebellum Back/bottom of brain Coordinates muscles to produce movement; regulate posture & balance 19a) Outline the functional differences between the SYMPATHETIC and the PARASYMPATHETIC divisions of the autonomic nervous system. Sympathetic nervous system: fight or flight response specific areas of your body are targeted by adrenaline (epinephrine) to increase glucose & oxygen in your blood and take away waste products of cellular respiration faster Parasympathetic system: rest & digest when your body is doing what it normally does at its normal pace; digesting food, making urine, etc 19b) Give an example of a situation in your life when your SYMPATHETIC division might be active. Earthquake; scary movie; hear a loud BANG! ; on a roller coaster 20) Why do you think the hypothalamus is sometimes called the autonomic nervous center? Hypothalamus is in charge of so many involuntary actions that it can seem as if it runs the whole autonomic nervous system 21) What conditions must be met in order for neurons to repair themselves? 1) neurilemma intact (cell membrane of the neuron) 2) cell body intact 3) no scarring 22) Briefly describe the main symptoms of the following conditions. Parkinson s Disease: appears is older people (around 60), they show symptoms such as tremors & stiffness of limbs, slowness of movement, impaired balance & coordination; caused by the death of specific neurons in the brain Migraine: caused by swelling of the blood vessels around the head which result from stress or hormonal changes. Symptoms of the condition include throbbing head, nausea/vomiting, sensitivity to light/noise/odor Epilepsy: abnormal brain signals which leads to muscle spasms and seizures Schizophrenia: symptoms that include hearing internal voices, hallucinations, delusions, paranoia Huntington s disease: genetically caused disease which doesn t appear until around age 40. This condition causes degeneration of brain cells which leads to uncontrolled muscle movements & loss of intellectual faculties Dementia: loss of mental skills that result from changes in or damage to the brain (stokes, tumors, head injuries, Alzheimer s). Symptoms include memory loss, difficulty performing tasks, problems with language, disoriented to time and place
Alzheimer s: condition appears later in life and is caused by brain lesions or plaques that accumulate causing specific brain cells to die. Symptoms include memory loss, confusion, and difficulty learning & remembering new information Cerebral Palsy: a person is usually born with this neurological disorder and it is caused by damage/abnormalities in parts of the brain that control muscle movement. A person with this condition has symptoms such as problems with body movement (muscle spasms) & posture Multiple Sclerosis: myelin has been damaged by their body s own immune system (autoimmune disease) and their symptoms include weakness, vision loss, and muscle spasms Meningitis: caused by a viral or bacterial infection and results in the inflammation of the meninges & cerebrospinal fluid. Symptoms include severe headache, high fever, stiff neck, nausea, and seizures Stroke: ruptured blood vessels or blockage of blood vessels which cause brain cells to die due to lack of oxygen Last 2 are from notes & Deadly Five article questions