Flashcards
BIOM1052 - Nervous System
Cards in this deck (119)
- 1What is the central nervous system?Brain and spinal cord
- 2What is the peripheral nervous system?Cranial nerves, ganglia outside CNS, spinal nerves
- 3What is the afferent and efferent divisions of the PNS?Afferent - sensory info to CNS
Efferent - motor commands from CNS - 4Describe a bipolar neuron.- one axon
- one dendrite
- special senses - 5Describe a unipolar neuron.- single fused process (dendrites and axon)
- cell body to side
- most sensory neurons - 6Describe a multipolar neuron.- two or more dendrites and one axon
- motor neurons - 7Draw a bipolar, unipolar and multipolar neuron.
- 8What are glia cells main role?They support neurons in PNS and CNS
- 9Describe astrocytes.They are found in the CNS only and are the most abundant glial cells. They form the blood brain barrier and help maintain extracellular chemical composition and provide structural support.
- 10Describe oligodendrocytes.They provide myelination of CNS axons which increases conductivity speed.
- 11Describe ependymal cells.These are epithelial cells in the CNS which line cavities containing cerebrospinal fluid such as ventricles in the brain and the central canal in the spinal cord. They function to produce and circulate cerebrospinal fluid from blood.
- 12Describe microglia.These are part of the immune system in the CNS and act as phagocytic cells to clear debris, waste and pathogens.
- 13Describe schwann cells.Provide myelination of PNS axons.
- 14Describe satellite cells.Surround cell bodies in ganglia of PNS and regulate the exchange with interstitial fluid.
- 15What are bundles of nerves called in the PNS or CNS?PNS - nerves (mixed nerves)
CNS - tracts - 16What are clusters of cell bodies called in the PNS or CNS?PNS - ganglia
CNS - nuclei - 17What are the three layers of connective tissue of a nerve and describe them.Epineurium - fibrous outer sheath
Perineurium - separates axon bundles into fascicles
Endoneurium - around individual neurons - 18Describe ganglia.Axons (sensory and motor) join the cell bodies in ganglia which is surrounded by epineurium.
- 19Describe white matter.Contains tracts and the colour is from myelin.
- 20Describe grey matter.Contains nuclei and colour is from cell bodies.
- 21Describe graded potentials.Can be depolarisation or hyperpolarisation, vary in magnitude and are local.
- 22Describe action potentialsDepolarisation only, all or nothing response and travels along the axon.
- 23How long is the spinal cord?It extends from the brain stem and is shorter than the vertebral column.
- 24Where do roots of spinal nerves emerge from?The spaces between vertebrae (intervertebral foramen)
- 25What are the three spinal meninges? Describe them.The three membranes that protect the spinal cord are dura mater, arachnoid mater and pia mater.
Dura mater - outer fibrous sheath
Arachnoid mater - middle membrane
Pia mater - inner membrane bound to spinal cord, provide support to blood vessels - 26Where is the epidural space?Between the dura mater and vertebrae, there is loose connective tissue, blood vessels and adipose tissue.
- 27Where is the subarachnoid space and what does it contain?It is between the arachnoid and pia mater, it contains cerebrospinal fluid which is a shock absorber and diffusion medium.
- 28What are the three grey matter horns of the spinal cord? Describe them.Dorsal (posterior) horn - cell bodies of interneurons receiving sensory information
Ventral (anterior) horn - cell bodies of Somatic motor neurons
Lateral horn - cell bodies of autonomic motor neurons - 29What are the different tracts in white matter of the spinal cord? Describe them.Ascending tracts - sensory information to brain
Descending tracts - motor commands to spinal cord - 30What are the two roots that neurons can enter/exit the spinal cord? Describe them.Dorsal root - sensory (afferent) neurons
Ventral root - motor (efferent) neurons - 31Describe spinal nerves.Dorsal and ventral roots fuse to form a spinal nerve of mixed neurons with 31 pairs in the body.
- 32How are peripheral nerves formed?Spinal nerves branch into rami and may converge into nerve plexus and eventually peripheral nerves are formed.
- 33Describe the two different types of reflex routes.Monosynaptic - one synapse between afferent and efferent neuron
Polysynaptic - more than one synapse (involve interneurons) - 34What are the five components of a reflex arc?1. Receptor
2. Sensory neuron
3. Integration centre
4. Motor neuron
5. Effector - 35Describe the stretch reflex.Allows adjustment to posture in response to stimuli from within a muscle. Change in muscle length is detected and same muscle is contracted.
- 36Describe the steps in a stretch reflex.1. Stimulus - stretch of muscle
2. Sensory neuron sends AP to spinal cord
3. Sensory neuron synapses with alpha motor neuron
4. AP of motor neuron causes contraction of same muscle - 37Describe the withdrawal reflex and steps involved.This reflex move the body away from a pain stimulus.
1. Sensory neuron send AP to spinal cord
2. Synapses with interneuron
- excitatory stimulates motor neuron to contract
- inhibitory stimulates motor neuron to relax
3. AP also sent to brain - 38Describe the crossed extensor reflex.It is a contralateral reflex where there is a motor response on the opposite side to stimulus. Occurs with withdrawal reflex and allows the other limb to bear the weight of the body. Injured limb flexes while healthy limb extends.
- 39What are the four things that provide protection and nourishment to the brain?Skull, meninges, cerebrospinal fluid (CSF) and blood brain barrier
- 40What are the three layers of the cranial meninges?Dura mater
Arachnoid mater
Pia mater - 41Describe the dura mater.Composed of two layers with blood filled space in between, this space is the dural sinus.
- 42Describe the arachnoid mater.Contains subarachnoid space with CSF.
- 43Describe the pia mater.This layer sticks to the surface of the brain.
- 44What is the role of cerebrospinal fluid?To cushion and nourish the brain and spinal cord.
- 45Where is cerebrospinal fluid produced?In choroid plexuses of the ventricles.
- 46Describe the choroid plexus.They are special areas with ependymal cells and leaky capillaries. The cells maintain the composition of cerebrospinal fluid.
- 47Explain the circulation of cerebrospinal fluid.Circulated through ventricles (brain) and central canal (spinal cord) and escapes through openings into subarachnoid space. It enters the venous blood through arachnoid villi. Cerebrospinal fluid is created from blood then recycled back into blood.
- 48Describe the blood brain barrier.Formed by tightly adhered capillary cells with the help of astrocytes that signal the cells to 'get tight'.
- 49How must molecules pass through the blood brain barrier?Must pass directly through the capillary cells by diffusion or transport proteins. Large and polar molecules cannot pass by diffusion and only pass with help of protein.
- 50What are the four main regions of the brain?Cerebrum
Diencephalon
Cerebellum
Brain stem - 51What makes up the diencephalon?The thalamus and hypothalamus
- 52What makes up the brain stem?Mid brain, pons and medulla oblongata
- 53How many hemispheres are in the cerebrum and how are they joined?Two - left and right joined by the corpus callosum
- 54What are the three type of surface features present on the cerebrum?Gyri - elevated ridges
Sulci - shallow depressions
Fissures - deep depressions - 55What are the two parts of the cerebrum and what are their main difference?Cerebral cortex - outer shell of grey matter
Basal nuclei - inner core of grey matter - 56What are the four lobes of the cerebral cortex?Occipital
Temporal
Parietal
Frontal - 57Describe the insula.It is an island of cortex medial to the lateral sulcus.
- 58What does the cerebral cortex play a key role in?Sensory perception and motor output.
- 59Describe the parietal lobe.It is the primary sensory cortex and controls perception of the general senses as well as awareness, location and intensity.
- 60What is the sensory homunculus?It is the sensory 'little man' that represents the sensitivity of each body region.
- 61Describe the frontal lobe.It is the primary motor cortex which processes voluntary control over skeletal muscle which is fine tuned by lower brain centres. It receives instructions from somatic motor association areas to activate motor neurons but not initiate motor activity.
- 62What is the motor homunculus?It is the motor 'little man' where more area is devoted to areas with fine motor control like the hands.
- 63Describe the prefrontal cortex.It controls planning and problem solving, directs attention, decision making, creativity and personality traits.
- 64Describe the limbic system.It is a functional group of structures around cerebrum and diencephalon. The functions include emotions, survival behaviour, socio-sexual behaviour, motivation and reward and processing memories.
- 65Describe the basal nuclei.It is the integrator of movement which is the subconscious control of skeletal muscle tone and coordination of learned movement patterns like walking. It inhibits unwanted movement and muscle tone.
- 66Describe the cerebellum.It is the coordinator and predictor of movement which refines planned movements to correct inn response to sensory information. It helps us maintain balance and posture.
- 67Describe the thalamus.It is the 'gatekeeper' to the cortex and almost all sensory information synapses here. Motor information from cerebellum and basal nuclei travel through thalamus to cortex and plays an important role in consciousness.
- 68Describe the hypothalamus.It is the homeostatic control, plays endocrine roles of hormone secretion, emotional and behavioural drives and control of autonomic functions.
- 69Describe the brain stem.Highway between spinal cord and higher brain structures, autonomic control centre for cardiovascular and respiratory systems, controls awakening and alertness, attachment of most cranial nerves and subconscious control of skeletal muscle movement.
- 70Describe cranial nerves.PNS nerves that connect to brain rather than spinal cord.
- 71How many cranial nerves are there?12 pairs
- 72Briefly describe the autonomic nervous system.Involuntary actions that control gland, cardiac muscle, smooth muscle and adipose tissue. The ANS maintains homeostasis.
- 73What are the two divisions of the ANS?The sympathetic and parasympathetic
- 74Does the sympathetic and parasympathetic divisions innervate the same organs?Yes but usually have an opposite effect.
- 75Describe the sympathetic nervous system.It is the fight or flight response including mental alertness, increased metabolic rate, reduced digestion, activation of energy stores, increased respiration and dilation of airways, increased heart rate and blood pressure, activation of sweat glands.
- 76Describe the parasympathetic nervous system.It is the rest and digest response including decreased metabolic rate, decreased heart rate and blood pressure, increased salivation and digestion, increased motility and blood flow in digestive tract, stimulation of urination and defecation.
- 77When at rest, what level of activity does each ANS division have?Each division has some level of activity causing a basal rate of activity which is the autonomic tone.
- 78What function does a autonomic tone serve?Allows ANS to both decrease or increase activity as required.
- 79How many motor neurons are in a ANS motor neuron chain?Two, they synapse at an autonomic ganglion is the PNS.
- 80Describe preganglionic neurons.Cell bodies in CNS, axons are preganglionic fibres.
- 81Describe ganglionic neurons.Cell bodies in autonomic ganglia, axons are postganglionic fibres.
- 82Where are the cell bodies of the preganglionic neurons located for the sympathetic NS?In the lateral horn of the spinal cord.
- 83Where do preganglionic fibres leave the spinal cord for the sympathetic NS?The ventral roots - thoracic and superior lumbar sections.
- 84What are the relative lengths of pre and postganglionic fibres for the sympathetic NS?Preganglionic are mostly short while postganglionic are mostly long.
- 85How does the adrenal medullae supplement the sympathetic NS?The sympathetic NS innervates the adrenal medulla which can release large quantities of epinephrine and norepinephrine into the blood. Lasts 5 - 10 times longer than direct stimulation and has a strong effect on metabolism reaching every cell in the body.
- 86Where are the cell bodies of the preganglionic neurons located for the parasympathetic NS?In the brain stem and sacral segment of the spinal cord.
- 87What are the relative lengths of pre and postganglionic fibres for the parasympathetic NS?Preganglionic mostly long while postganglionic mostly short.
- 88What neurotransmitter do ANS preganglionic fibres release?Acetylcholine (Ach)
- 89What neurotransmitter do parasympathetic NS postganglionic fibres release?Ach
- 90What neurotransmitter do sympathetic NS postganglionic fibres release?Most release norepinephrine (NE) with some releasing Ach
- 91What cells contain cholinergic receptors?Cells that respond to Ach
- 92What are the two cholinergic receptors and describe them.Nicotinic receptors - all ganglionic neurons, contain cation channels
Muscarinic receptors - all parasympathetic target organs, G-protein coupled receptors - 93Describe adrenergic receptors.Bind epinephrine and noepinephrine with different affinities. Found on sympathetic target organs and are G-protein couple receptors.
- 94Can ANS reflexes be localised?Yes
- 95How are ANS reflexes localised?Through visceral reflexes allowing local control without 'whole body' response.
Eg. swallowing reflex, pupil dilation - 96Describe sympathetic mass discharge and what causes it.Occurs when hypothalamus stimulated by fright, fear or pain. General fight or flight response to whole body through hormonal discharge by adrenal medullae.
- 97What must stimulus energy be converted into before it can be perceived?Electrical energy through sensory transduction
- 98Describe sensory transduction.Stimuli causes change in membrane potential at sensory receptor, cation channels open with graded potential in receptor and action potential in afferent neuron.
- 99What are the two forms of sensory receptors in regards to afferent neurons?Specialised ending of an afferent neuron or separate receptor cell
- 100How is the potential transferred to the afferent neuron when the receptor is a separate receptor cell?The release of neurotransmitter by the receptor cell caused action potential in afferent neuron.
- 101What three bits of information does the brain need to interpret a stimulus?Type, intensity and location of stimulus.
- 102How can the brain identify the stimulus type?Each stimulus type causes stimulation of the cortex through a different labelled line. The area of the cortex at the end of the labelled line is also important for recognition of stimulus type.
- 103What are the two factors in which stimulus intensity can be determined?Frequency of action potentials and number of receptors activated.
- 104How is stimulus location identified?Determined by stimulation of receptive field which is the area monitored by a single sensory neuron.
- 105What are the two types of receptors in regards to adaptation?Phasic and tonic receptors
- 106Describe tonic receptors.Adapt slowly or not at all and have a constant response to stimuli such as pain receptors.
- 107Describe phasic receptors.Adapt quickly and responds to changes in the stimuli such as pressure receptors.
- 108What are the four types of receptors?Mechanoreceptors, thermoreceptors, nociceptors and chemoreceptors.
- 109Describe tactile receptors in skin.Mechanoreceptors providing information about touch, pressure and vibration.
- 110What are the six type of tactile receptors in the skin?1. Free nerve endings
2. Root hair plexus
3. Tactile discs
4. Tactile corpuscles
5. Lamellated corpuscles
6. Ruffini corpuscles - 111Describe nociceptors and the different types.Pain receptor including mechanical, thermal and polymodal nociceptors. These are associated with behavioural responses (reflex) and emotional response (crying, fear).
- 112What are the two types of pain?Fast and slow pain
- 113Describe fast pain.Mechanical and thermal nociceptors with sharp prickling sensation. These are easily located and transmitted over A-delta fibres (myelinated).
- 114Describe slow pain.Polymodal nociceptors with dull aching sensation. These are poorly located and transmitted over C fibres (unmyelinated).
- 115Describe thermoreceptors in the skin.Two types, warmth and cold with extremes detected by nociceptors. Perception of temperature depends on combination and intensity of receptor stimulation.
- 116Are thermoreceptors tonic or phasic?Fast adapting phasic receptors that respond strongly to changes in temperature.
- 117Describe the somatic nervous system.Division of PNS that controls skeletal muscle.
- 118Describe the two ways in which neural activity influences strength of muscle contraction.1. Motor unit recruitment - more motor units increases contraction strength
2. Frequency of action potentials - increases tension in muscle fibres causing continuous contraction - 119What is a neuromuscular junction?Where axon terminals and muscle fibres connect. Each muscle fibre only has one neuromuscular junction with a single axon terminal.
Information
- Description
- Flashcards on BIOM1052 - Nervous System, created by Zoe Thomas on 16/08/2015.
- Created by
- Zoe Thomas · Aug 2015
- Updated
- Feb 19, 2016
- Views
- 3
- Rating