2. nervous system Flashcards

Question

parieto-occipital sulcus and calcarine sulcus

Answer 1

parieto-occipital sulcus: between parietal and occipital lobes calcarine sulcus: within the occipital lobe (primary visual cortex)

Answer 2

grey matter= cell bodies white matter= myelinated axons

Answer 3

1. anterior 2. posterior 3. flocculonodular lobe ('little brain'= movement and control centre)

Answer 4

regulation of vital body functions e.g. breathing, body temp, consciousness, sleep/wake cycle etc.

Answer 5

1. midbrain vision, hearing, motor control 2. pons location of pneumotaxic centre and handles unconscious processes and jobs, such as your sleep-wake cycle and breathing. 3. medulla oblongata cardiac, respiratory, vasomotor, vomiting brainstem*regulation of vital body functions e.g. breathing, body temp, consciousness, sleep/wake cycle etc

Answer 6

4 cavities in the brain which are interconnected. lateral ventricles (x2), third and fourth ventricles. filled with cerebrospinal fluid (CSF) produced by choroid plexus.

Answer 7

specialised ependymal cells CSF is produced by specialized ependymal cells in the choroid plexus of the ventricles of the brain, and absorbed in the arachnoid granulations.

Answer 8

3 membranes called the meninges

Answer 9

brain and spinal cord do not come into direct contact with bone (skull and vertebral column). CNS is protected by 3 membranes called the meninges. 1. dura mater tough, outer layer skull cap 2. arachnoid 'spider web' layer under dura 3. pia mater thin, inner layer close to surface of CNS space between arachnoid and pia is filled with CSF: subarachnoid space

Answer 10

space between arachnoid and pia which is filled with CSF. dura mater->arachnoid->pia mater (meninges)

Answer 11

tube-like structure composed of grey and white matter. permits communication between the brain and the body. relays information to/from skin, joints, muscles. brain is not always involved- reflexes. spinal cord communicates via spinal nerves (PNS)

Answer 12

spinal cord

Answer 13

31 spinal cord segments: cervical (8 segments: C1-C8) thoracic (12 segments: T1-T12) lumbar (5 segments: L1-L5) sacral (5 segments: S1-S5) coccygeal (1 segment: co) each spinal segment has paired spinal nerves.

Answer 14

The dorsal horn is the location of sensory (afferent) synapses, the ventral horn is the location of motor (efferent) neuron cell bodies, and the lateral horn is the location of cell bodies of the autonomic nervous system. dorsal= back ventral= front

Answer 15

The intermediate zone of spinal cord refers to the region of grey matter located between the posterior (dorsal) and anterior (ventral) horns of the spinal cord

Answer 16

The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it receives cerebrospinal fluid, and shares the same ependymal lining.

Answer 17

ascending sensory axons. The dorsal column, also known as the dorsal column medial lemniscus (DCML) pathway, deals with the conscious appreciation of fine touch, two-point discrimination, conscious proprioception, and vibration sensations from the entire body except for the head.

Answer 18

lateral funiculus: ascending and descending ventral funiculus: descending axons A single dorsal funiculus is located on the dorsal aspect of the spinal cord and a single ventral funiculus is located on the ventral aspect of the spinal cord. Each side of the spinal cord has a lateral funiculus. Each funiculus can be subdivided into smaller function groups called a fasciculi. [The dorsal column and dorsal horn are on the posterior side of the spinal cord. The ventral column and ventral horn are located on the anterior side of the spinal cord. The lateral column and lateral horn are located in the middle.]

Answer 19

The grey matter also extends from the brain into the spinal cord. The grey matter creates a hornlike structure throughout the inside of the spinal cord while the white matter makes up the surrounding sections of the spinal cord. The grey matter does extend to the spinal cord to make signaling more effective.

Answer 20

nerve cell: specialised cell which receive, process, and transmit info via electrochemical signalling.

Answer 21

1. number of neurites (axons and dendrites) 2. dendritic tree structure (pyramidal or stellate, spiny or aspinous) 3. axon length (projection or local circuit neurons) 4. neurotransmitter (cholinergic etc) 5. connections (sensory neurons-afferent, interneurons, motorneurone-efferent)

Answer 22

afferent = sensory efferent = motor Afferent neurons carry information from sensory receptors found all over the body towards the central nervous system, whereas efferent neurons carry motor information away from the central nervous system to the muscles and glands of the body in order to initiate an action.

Answer 23

number of axons and dendrites. based on the total number of neurites extending from the cell body (soma). - unipolar - bipolar - pseudounipolar - multipolar

Answer 24

two principal types found in the cerebral cortex: pyramidal (spiny dendrites) stellate (star-shaped; spiny or aspinous)

Answer 25

A large apical dendrite grows from the upper pole of the soma and bifurcates distally giving rise to the apical tuft, while short basal dendrites grow from the base of the soma. These two domains differ in terms of morphology, afferent connections, and ion channel distributions. The apical and basal dendrites are oriented in opposite directions and occupy different layers, with apical dendrites extending toward the hippocampal fissure through the stratum radiatum and stratum lacunosum-moleculare, and basal dendrites extending in the opposite direction through the stratum oriens. The striatum oriens is the most dorsal (towards back of body) layer of the hippocampus

Answer 26

projection neurones: long axons, e.g. pyramidal cells of cerebral cortex, Golgi type I local circuit neurones: short axons, e.g. stellate cells of cerebral cortex, Golgi type II, interneurones

Answer 27

Type I= projection neurones Type II= local circuit neurones Golgi type I neurons have very long axons that connect different parts of the system; Golgi type II neurons, also known as microneurons, have only short axons or sometimes none.

Answer 28

*classification based on the neurotransmitter released at their synapses acetylcholine- cholinergic glutamate- glutamatergic GABA- GABAergic noradrenaline- noradrenergic dopamine- dopaminergic histamine- histaminergic serotonin- serotininergic

Answer 29

1. sensory (afferent) neurones: relay sensory info from the body's sensory surfaces towards the CNS e.g. skin temperature, pain etc. 2. interneurones: form connections between neurones- neural circuits 3. motorneurons (efferent): carry nerve impulses away from the CNS to muscles- contraction of muscle

Answer 30

The dorsal root ganglion is a swelling on a nerve that joins the spinal cord. It contains nerves that carry sensations from different parts of your body.

Answer 31

one or more regions within the CNS that relay impulses from sensory to motor neurones *a critical component in the nervous system that processes sensory information and coordinates appropriate motor responses.

Answer 32

responds to a stimulus by producing a generator or receptor potential a nerve ending that sends signals to the central nervous system when stimulated, allowing the brain to receive information from various systems and body parts both internally and externally.

Answer 33

muscle or gland that responds to motor nerve impulses Motor neurons carry out-going signals from the brain or spinal cord to the effector organs, namely the muscles and glands.

Answer 34

axon conducts impulses from receptor to integrating centre Sensory neurons are the nerve cells that are activated by sensory input from the environment - for example, when you touch a hot surface with your fingertips, the sensory neurons will be the ones firing and sending off signals to the rest of the nervous system about the information they have received.

Answer 35

axon conducts impulses from integrating centre to effector part of the central nervous system (CNS) and connect to muscles, glands and organs throughout the body. These neurons transmit impulses from the spinal cord to skeletal and smooth muscles (such as those in your stomach),

Answer 36

via the dorsal root

Answer 37

via the ventral root

Answer 38

the peripheral nervous system *afferent and efferent nerve fibres travel together in mixed spinal nerves

Answer 39

hydrophobic interior is a barrier to passage of water soluble substances between ICF and ECF *intracellular fluid and extracellular fluid

Answer 40

phospholipids constantly move so the membrane is 'fluid'

Answer 41

head= hydrophillic/polar tail= hydrophobic/non-polar a lipid molecule with a polar, water-attracting head made of a phosphorylated alcohol, and a hydrophobic, water-repelling tail made of two fatty acid chains. Phospholipids consist of a glycerol molecule, two fatty acids, and a phosphate group that is modified by an alcohol. The phosphate group is the negatively-charged polar head, which is hydrophilic.

Answer 42

potential difference is the difference in potential between two points (e.g. either side of a membrane). *the potential charge transfer is the impermeable membrane was removed

Answer 43

measurable by placing an electrode inside the cell and measuring vs bath electrode, out side the cell. potential always quoted as inside vs outside.

Answer 44

depends on what is inside vs outside the cell - charges ions membrane + membrane components are crucial. What generates the resting membrane potential is the K+ that leaks from the inside of the cell to the outside via leak K+ channels and generates a negative charge in the inside of the membrane vs the outside. At rest, the membrane is impermeable to Na+, as all of the Na+ channels are closed. moves three positively charged sodium ions out of the cell and only brings in two positively charged potassium ions. In a normal neuron there is a greater concentration of sodium outside the cell and a greater concentration of potassium inside the cell. Therefore the K+ ions want to leave and a negative cell interior environment is established

Answer 45

arises when there is a difference in the electrical charge on the two sides of a membrane, due to a slight excess of positive ions over negative ones on one side and a slight deficit on the other.

Answer 46

K+ ions have a higher permeability (25-30 compares to 1)

Answer 47

narrow, water-filled tunnels that allow only ions of a certain size and/or charge to pass through. This characteristic is called selective permeability.

Answer 48

Na+ channels shift the membrane potential in a positive direction, K+ channels shift it in a negative direction (except when the membrane is hyperpolarized to a value more negative than the K+ reversal potential), and Cl− channels tend to shift it towards the resting potential. Changing the number of open ion channels provides a way to control the cell's membrane potential and a great way to produce electrical signals. Neurotransmitters that act to open Na+ channels typically cause the membrane potential to become more positive, while neurotransmitters that activate K+ channels typically cause it to become more negative; those that inhibit these channels tend to have the opposite effect

Answer 49

K+ acting alone would establish an equilibrium potential of -90mV

Answer 50

Na+ acting alone would establish an equilibrium potential of +60mV

Answer 51

25 - 30 times. *resting membrane potential is closer to K+ equilibrium potential

Answer 52

K+ acting alone would establish an equilibrium potential of -90mV Na+ acting alone would establish an equilibrium potential of +60mV resting membrane is 25 to 30 times more permeable to K+ than to Na+. so resting membrane potential is closer to K+ equilibrium potential

Answer 53

changes in membrane potential fundamentally underlie the entire operation of the nervous system both physiologically and pathophysiologically - synaptic transmission - network communication -all the sensory systems - much more??? these processes could not occur without the establishment of an initial resting membrane potential

Answer 54

1. graded potentials (act as short-distance signals) 2. action potentials (act as long-distance signals) *graded potentials are not fully propagated and tend to decrease in strength as they spread along the membrane. They must either summate in time or space to generate a strong enough signal to trigger an action potential. Graded potentials are variable-strength signals that can be conveyed over small distances, whereas action potentials are massive depolarizations that can be transferred over long distances.

Answer 55

opening of Na+ channels

Answer 56

Ligand-gated ion channels (LGICs) are integral membrane proteins that contain a pore which allows the regulated flow of selected ions across the plasma membrane. Ion flux is passive and driven by the electrochemical gradient for the permeant ions. ligand is defined as any molecule or atom that irreversibly binds to a receiving protein molecule, otherwise known as a receptor. When a ligand binds to its respective receptor, the shape and/or activity of the ligand is altered to initiate several different types of cellular responses.

Answer 57

the process in which a chemical signal is released from one neuron and diffuses to other neurons or target cells, generating a signal that excites, inhibits, or modulates cellular activity.

Answer 58

The secretory vesicle is a vesicle that mediates the vesicular transport of cargo - e.g. hormones or neurotransmitters - from an organelle to specific sites at the cell membrane, where it docks and fuses to release its content.

Answer 59

the space in between the axon of one neuron and the dendrites of another and is where the electrical signal is translated to a chemical signal that can be perceived by the next neuron.

Answer 60

Graded potentials refer to changes in the conductance of a sensory receptor cell's membrane, primarily caused by sensory input. These potentials can also occur at localized points on the cell membrane due to excitatory or inhibitory synapses. occurs in active area of the membrane the magnitude of a graded potential varies directly with the magnitude of the stimulus graded potentials spread decrementally by local current flow flow is between the active area and adjacent inactive areas graded potentials die out over a short distance magnitude depends on the extent of stimulation i.e. depends on quantity of ligand reaching neuron example 1: one synapse with neuron (acting briefly): small depolarisation. more synapses (firing simultaneously): large depolarisation example 2: one synapse repeatedly firing: large depolarisation adding together of stimuli= summation

Answer 61

the adding together of stimuli

Answer 62

spatial temporal

Answer 63

excitatory post-synaptic potential = an individual graded potential from a synapse

Answer 64

one synapse with neuron (acting briefly): small depolarisation more synapses (firing simultaneously): large depolarisation Spatial summation involves simultaneous signals coming from multiple presynaptic neurons being received by a single postsynaptic neuron. Temporal summation involves a single presynaptic neuron rapid-firing signals to a postsynaptic neuron.Temporal summation describes the rate of EPSPs from a single source (one post synaptic neuron firing at a high frequency), whereas spatial summation describes the accumulation of EPSPs from multiple sources (many neurons firing at a low rate).

Answer 65

one synapse repeatedly firing: large depolarisation Temporal summation describes the rate of EPSPs from a single source (one post synaptic neuron firing at a high frequency), whereas spatial summation describes the accumulation of EPSPs from multiple sources (many neurons firing at a low rate). Spatial summation involves simultaneous signals coming from multiple presynaptic neurons being received by a single postsynaptic neuron. Temporal summation involves a single presynaptic neuron rapid-firing signals to a postsynaptic neuron.

Answer 66

if enough EPSPs add together, the threshold potential is reached TP is (in general) -55mV e.g. EPSPs of 5mV each: -70mV + (3x+5mV) = -55mV when TP is reached, depolarisation 'runs away' goes all the way into the positive peaks at (typically) ca. +35mV (may be much more, in some neuron types; up to ca. +100mV **this is the action potential

Answer 67

a rapid sequence of changes in the voltage across a membrane; membrane voltage/potential is determined at any time by the relative ratio of ions, extracellular to intracellular and the permeability of each ion APs travel along axons APs = nerve impulses

Answer 68

In electrophysiology, the threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential. In neuroscience, threshold potentials are necessary to regulate and propagate signaling in both the central nervous system (CNS) and the peripheral nervous system (PNS).

Answer 69

Neurons and muscle cells are excitable such that these cell types can transition from a resting state to an excited state. The resting membrane potential of a cell is defined as the electrical potential difference across the plasma membrane when the cell is in a non-excited state.

Answer 70

The action potential is an explosion of electrical activity that is created by a depolarizing current. This means that some event (a stimulus) causes the resting potential to move toward 0 mV. When the depolarization reaches about -55 mV a neuron will fire an action potential.

Answer 71

The breach of the threshold potential in a neuron triggers the action potential, a crucial process in nerve signal transmission. When the threshold potential is reached, it causes a rapid, positive feedback loop that leads to the "runaway effect" of depolarization The runaway effect refers to the fact that once the threshold potential is breached, the process of depolarization becomes self-perpetuating (a positive feedback loop) until it reaches its peak. This is essential for the rapid transmission of nerve signals. After reaching the peak, potassium channels open to restore the membrane potential, and the neuron returns to its resting state. Voltage-Gated Sodium Channels Open: Once the threshold is breached, it causes the opening of voltage-gated sodium (Na⁺) channels, allowing sodium ions to flood into the neuron. Positive Feedback Loop: As sodium enters, the inside of the neuron becomes more positive, which causes more sodium channels to open. This rapid influx of sodium ions leads to a drastic change in the membrane potential, creating the "runaway" depolarization.

Answer 72

After initiation, action potentials travel down axons to cause release of neurotransmitter. Dendrite – The receiving part of the neuron. Dendrites receive synaptic inputs from axons, with the sum total of dendritic inputs determining whether the neuron will fire an action potential.

Answer 73

axon diameter. myelinates fibres are faster *autonomic: smooth/cardiac muscle 0.3-1.3 micrometer (unmyelinated) 0.7-2.2 m/sec pain 1-5 micrometer (unmyelinated and myelinated) 12-30 m/sec sensory: muscle position 12-22 micrometer (myelinates) 70-120 m/sec approx. range 1-270mph Larger diameter axons conduct faster due to less resistance, and myelinated axons speed up conduction by reducing membrane capacitance

Answer 74

Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells. If myelin is damaged, these impulses slow down.

Answer 75

active node at peak of action potential adjacent inactive node into which depolarisation is spreading: will soon reach threshold remainder of nodes still at resting potential local current flow that depolarises adjacent inactive node from resting to threshold direction of propagation of action potential previous active node returned to resting potential; no longer active adjacent node that was threshold by local current flow now active at peak of action potential new adjacent inactive node into which depolarisation is spreading; will soon reach threshold axon segment depolarization to threshold, opening of voltage-gated Na+ channels, influx of Na+, local current flow to nearby axon segment, and AP generation in the adjacent axon segment. the process by which an electrical impulse travels along the membrane of a nerve cell. This action allows for the communication of information throughout the nervous system he depolarisation of the previous region of the axon triggers the depolarisation of the subsequent region of the axon, so the action potential moves along the axon

Answer 76

saltatory means 'to jump' occurs in myelinated nerve fibres propagates action potential 50x faster than contiguous conduction by local currents, an action potential at one node produces an action potential at the next node they impulse 'jumps' from node to node, skipping over the myelinated sections of the axon the rapid method by which nerve impulses move down a myelinated axon with excitation occurring only at nodes of Ranvier

Answer 77

transfer of info from one neuron to the next occurs via a synapse. When neurons communicate, an electrical impulse triggers the release of neurotransmitters from the axon into the synapse. The neurotransmitters cross the synapse and bind to special molecules on the other side, called receptors. Receptors are located on the dendrites. Receptors receive and process the message.

Answer 78

the junction between neurons

Answer 79

1. electrical neurons connected directly by gap junctions 2. chemical chemical messenger is transmitted across the junction separating neurons

Answer 80

neurons connected directly by gap junctions bidirectional and very fast i.e. action potential in one cell can produce an almost instantaneous electrical potential in the neighbouring cell

Answer 81

chemical messenger is transmitted across the junction separating neurons most common form of transmission in mature nervous system no direct contact - 20-50mm synaptic cleft involved a junction between an axon terminal of one neuron and the dendrites or cell body of a second neuron first = presynaptic neuron second= postsynaptic neuron the presynaptic neuron releases neurotransmitter (NT) the NT binds to receptors on the postsynaptic neuron this produced a response in the postsynaptic neuron each presynaptic neuron always releases the same, single neurotransmitter

Answer 82

if binding of NT opens Na+ and K+ channels the result is a small depolarisation called an excitatory post-synaptic potential (EPSP) EPSP brings the cell closer to the threshold if binding of NT opens either K+ or Cl- channels the result is a small hyperpolarisation called an inhibitory post-synaptic potential (IPSP) IPSP means cell less likely to reach threshold

Answer 83

small depolarisation called an excitatory post-synaptic potential (EPSP) *EPSP brings the cell closer to threshold

Answer 84

hyperpolarisation called an inhibitory post-synaptic potential (IPSP) * IPSP means cell less likely to reach threshold

Answer 85

An excitatory transmitter promotes the generation of an electrical signal called an action potential in the receiving neuron, while an inhibitory transmitter prevents it EPSP vs IPSP

Answer 86

if excitatory inputs dominate, the cell is brought closer to threshold if inhibitory inputs dominate, the cell is taken farther from the threshold. if excitatory and inhibitory activity is balanced the membrane potential remains close to resting its the balance between all inhibitory and excitatory input which will determine if a neuron fires its own action potential ESPS vs ISPS PSPs are called excitatory (or EPSPs) if they increase the likelihood of a postsynaptic action potential occurring, and inhibitory (or IPSPs) if they decrease this likelihood. Summation is therefore a neurotransmitter-induced tug-of-war between all excitatory and inhibitory postsynaptic currents

Answer 87

EPSP and IPSP arrive via dendrites integration/summation occurs in the soma if threshold is reached AP is generated and propagated down the axon NT released from axonal terminals The neuron cell body acts as a computer by integrating (adding or summing up) the incoming potentials. The net potential is then transmitted to the axon hillock, where the action potential is initiated. Another factor that should be considered is the summation of excitatory and inhibitory synaptic inputs. *Temporal summation involves a single presynaptic neuron rapid-firing signals to a single postsynaptic neuron's synapse. Because the signals are received in rapid succession, they compound into a greater signal. Spatial summation involves multiple presynaptic neurons simultaneously sending signals to a single neuron. [Neuronal integration refers to the process of combining and processing incoming signals at the level of a single neuron to produce an output signal.]

Answer 88

to send messages from various parts of your body to your brain, and from your brain back out to your body to tell your body what to do. These messages regulate your: Thoughts, memory, learning and feelings. Movements (balance and coordination).

Answer 89

A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain.

Answer 90

CNS receives and processes sensory info, initiates responses, stores memories generates thoughts and emotions

Answer 91

CNS conducts signals to and from the brain, controls reflex activities

Answer 92

motor neurons CNS to muscles and glands sensory neurons sensory organs to CNS

Answer 93

the motor neurons into somatic NS and autonomic NS. autonomic nervous system into sympathetic and parasympathetic

Answer 94

(motor neurons of PNS) somatic; controls voluntary movements autonomic; controls involuntary responses

Answer 95

sympathetic and parasympathetic fight/flight vs rest/digest

Answer 96

1. frontal, 2. temporal, 3. parietal 4. occipital lobes

Answer 97

frontal lobe

Answer 98

problem solving, complex planning executive function, personality

Answer 99

planning, control and execution of voluntary movement premotor cortex supplementary motor area primary motor cortex (precental gyrus, M1) The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately anterior to the central sulcus. of the frontal lobe

Answer 100

production of speech usually found in left hemisphere Brocha's aphasia

Answer 101

Expressive aphasia (also known as Broca's aphasia) is a type of aphasia characterized by partial loss of the ability to produce language (spoken, manual, or written), although comprehension generally remains intact. A person with expressive aphasia will exhibit effortful speech. inability (or impaired ability) to understand or produce speech, as a result of brain damage.

Answer 102

processing of sensory info primary somatosensory cortex (S1) - postcentral gyrus - tactile sensation - sensory homunculus posterior parietal cortex - integration of sensory info - spatial attention - cognitive functions

Answer 103

visual processing centre of brain primary visual cortex (V1) - striate cortex (myelin) - located around calcarine sulcus - receives visual info from thalamus - organised into 6 layers - shape, size, position other areas of visual cortex; V2, V3. V4, V5

Answer 104

6 layers [The primary visual cortex, also known as V1 or Brodmann area 17, surrounds the calcarine sulcus on the occipital lobe's medial aspect]

Answer 105

processes sensory information; most commonly associated with processing auditory information and with the encoding of memory auditory cortex - hearing - speech, words - pitch, tone (music) wernicke's area - language comprehension other roles - long term memory formation - visual perception and recognition

Answer 106

temporal lobe *processes sensory info. auditory cortex (hearing, speech, words, pitch, tone-music); wernickes area (language comprehension); long term memory formation and visual perception and recognition **hippocampus also is the catalyst for long-term memory

Answer 107

temporal lobe.

Answer 108

parietal lobe

Answer 109

frontal lobe

Answer 110

occipital lobe

Answer 111

the complexity of the cortex and range of functions

Answer 112

afferent= sensory *transmits info from periphery to the CNS; contains receptors efferent= motor *transmits info from CNS to the rest of the body; sends motor info to effectors

Answer 113

1. somatic sensory receives sensory info from; skin, fascia, joints, skeletal muscles, special senses 2. visceral sensory receives sensory info from viscera *viscera= The internal organs of the body, specifically those within the chest (as the heart or lungs) or abdomen (as the liver, pancreas or intestines).

Answer 114

motor 1. somatic motor voluntary NS. innervates skeletal muscle 2. autonomic motor involuntary NS. innervates; cardiac muscle, smooth muscle, glands (parasympathetic- rest/digest and sympathetic- fight/flight)

Answer 115

afferent (sensory) and efferent (motor) nerve fibres *these fibres emerge from the brain and spinal cord to innervate every structure in the body cranial and spinal nerves

Answer 116

cranial- 12 pairs of nerves spinal- 31 pairs of nerves Cranial nerves transmit sensory information, including touch, vision, taste, smell, and hearing. Spinal nerves connect the spinal cord with other parts of the body.

Answer 117

supply (an organ or other body part) with nerves.

Answer 118

12- arise from base of the brain innervate the head (including special sense organs) can be sensory/motor/both sensory only= CrNI, II, VIII (sense organs) motor only= CrN III, IV and VI (eye muscles); XI (neck muscles), XII (tongue muscles) vagus nerve= CrN X (also innervates upper body)

Answer 119

sensory only= CrNI, II, VIII (sense organs) [1, 2, 8]

Answer 120

motor only= CrN III, IV and VI (eye muscles); XI (neck muscles), XII (tongue muscles) [CrN 3, 4, 6, 11, 12) Your cranial nerves are a set of 12 nerves that send electrical signals between your brain and different parts of your head, face, neck and torso

Answer 121

vagus nerve= CrN X (also innervates upper body) The vagus nerve (cranial nerve [CN] X) is the longest in the body, containing both motor and sensory functions in afferent and efferent regards. The nerve travels widely throughout the body, affecting several organ systems and regions of the body, such as the tongue, pharynx, heart, and gastrointestinal system.

Answer 122

31- one pair/spinal cord segment cervical C1-C8 thoracic T1-T12 lumbar L1-L5 sacral S1-S5 coccogeal Co afferent and efferent fibres; sensory (afferent) axons end in sensory receptors; motorneuron (efferent) axons end in effectors- muscle

Answer 123

muscle efferent= motorneuron

Answer 124

cervical C1-C8 = 8 thoracic T1-T12 = 12 lumbar L1-L5 = 5 sacral S1-S5 = 5 coccogeal Co = 1 31 pairs of spinal nerves; 1/segment

Answer 125

Dermatomes are areas of skin that send signals to the brain through the spinal nerves. areas of skin supplied by a single spinal nerve. sensory info from skin C1 nerve is the exception

Answer 126

C1 nerve (cervical)

Answer 127

dorsal refers to the back, or posterior, portion of the body, whereas ventral, or anterior, refers to the front part of the body

Answer 128

efferent (motor axon)= ventral - front afferent (sensory) fibre= dorsal - back

Answer 129

The peripheral nervous system (PNS) connects the central nervous system (CNS) to peripheral organs in the body with motor, sensory, and autonomous nerves. The PNS is not only responsible for bidirectional communication with the organs but also for interactions with other systems in the body

Answer 130

a rapid, involuntary movement in response to a stimulus completely subconscious

Answer 131

protection from harmful stimuli sneezing, coughing, vomiting homeostasis balance and posture

Answer 132

the simplest circuit in the nervous system *start with sensory receptors; end in effectors; do not reach consciousness

Answer 133

start with sensory receptors end in effectors do not reach consciousness

Answer 134

somatic reflex arcs monosynaptic: one synapse between a sensory (afferent) and motor (efferent) neuron. no interneurons. polysynaptic: one or more interneurons connect afferent and efferent neurones. Monosynaptic refers to the presence of a direct single synapse. No interneuron is present. By contrast, in polysynaptic reflex arcs, one or more interneurons connect afferent (sensory) and efferent (motor) signals. It causes the stimulation of sensory, association, and motor neurons.

Answer 135

Somatic reflexes involve specialized sensory receptors called proprioceptors that monitor the position of our limbs in space, body movement, and the amount of strain on our musculoskeletal system. The effectors involved in these reflexes are located within skeletal muscle. A somatic reflex is an involuntary movement in response to a stimulus. To produce the action, the somatic reflex arc is activated when a signal from the stimulus is sent to the muscle cells, passing through afferent neurons to the CNS, and finally, to the efferent neurons.

Answer 136

1. stretch reflex- stretch of muscle 2. hammer tap to patellar tendon 3. stretch of muscle spindle (sensory receptor) in quadriceps of muscle 4. sensory (afferent) fibres to spinal cord synapse with alpha motorneuron 5. motorneuron stimulates contraction of the quadriceps muscle (effector)

Answer 137

tendon jerk reflexes can be evoked from many muscles sensory receptor detects muscle stretch- leads to muscle contraction involves the somatic sensory and somatic motor divisions of the PNS somatic- voluntary movement control (skeletal muscle) somatic sensory (afferent) fibres from sensory receptors in skeletal muscle efferent motorneuron output to skeletal muscle (somatic motor) no involvement from interneurons- MONOSYNAPTIC

Answer 138

flexion (withdrawal reflex) *reciprocal inhibition

Answer 139

when the effector muscle contracts, the antagonist muscle relaxes Sherrington (1906) described reciprocal innervation as the process that controls agonist and antagonist muscle actions. One muscle group (agonists) must relax to allow another group (antagonists) to contract. This is called reciprocal inhibition. (polysynaptic) a general phenomenon in which the stretch of one muscle inhibits the activity of the opposing muscle. Reciprocal inhibition prevents muscles from working against each other when external loads are encountered.

Answer 140

In an antagonistic muscle pair, as one muscle contracts, the other muscle relaxes or lengthens. The muscle that is contracting is called the agonist and the muscle that is relaxing or lengthening is called the antagonist. e.g. the biceps (agonist) contracts, and the triceps (antagonist) relaxes

Answer 141

antagonist

Answer 142

closed loop - role in control of physiological variables e.g. muscle length - stimulus feedback causes response which acts on stimulus - muscle stretch leads to muscle contraction - tendon jerk reflex *corrections to movement plan; Closed-loop control means that there is some kind of position information that is fed back to the motion controller of a system and that is used in the positioning process. e.g. walking on ice

Answer 143

open loop - protection from potentially harmful stimuli - stimulus feedback has no effect on the stimulus - pin prick leads to withdrawal from pin (stimulus unchanged) - flexion withdrawal reflex Open-loop control is typically used in tasks that require quick reactions, such as reflex actions or pre-learned sequences like typing. In open-loop control, once a motor command is sent from the motor cortex, it does not receive feedback about the action's outcome until after it's completed.

Answer 144

protective (open loop)

Answer 145

control reflex (closed loop)

Answer 146

sensory info crosses spinal cord via interneurons

Answer 147

flexion withdrawal The crossed extensor reflex is a contralateral reflex that allows the body to compensate on one side for a stimulus on the other. For example, when one foot steps on a nail, the crossed extensor reflex shifts the body's weight onto the other foot, protecting and withdrawing the foot on the nail. stimulus causes flexion of leg (withdrawal); other leg must extend to support the weight of the body; prevents falling over; sensory info crosses spinal cord via interneurons

Answer 148

(sympathetic/parasympathetic) involuntary control of the body's internal environment. autonomic reflexes differ from somatic reflexes- efferent output. visceral efferent nerves to smooth muscle, cardiac muscle and glands. *somatic; one efferent neuron from CNS to skeletal muscle. AUTONOMIC; two neuron chain -synapse in a ganglion - pre and post ganglionic fibres [A ganglion is a collection of neuronal bodies found in the voluntary and autonomic branches of the peripheral nervous system (PNS). Ganglia can be thought of as synaptic relay stations between neurons. The information enters the ganglia, excites the neuron in the ganglia and then exits.]

Answer 149

synapse in a ganglion pre and post ganglionic fibres

Answer 150

A ganglion is a collection of neuronal bodies found in the voluntary and autonomic branches of the peripheral nervous system (PNS). Ganglia can be thought of as synaptic relay stations between neurons. The information enters the ganglia, excites the neuron in the ganglia and then exits.

Answer 151

1. sympathetic 2. parasympathetic 3. enteric

Answer 152

Your sympathetic nervous system is best known for its role in responding to dangerous or stressful situations. In these situations, your sympathetic nervous system activates to speed up your heart rate, deliver more blood to areas of your body that need more oxygen or other responses to help your get out of danger.

Answer 153

The parasympathetic nervous system is part of the body's autonomic nervous system. Its partner is the sympathetic nervous system, which control's the body's fight or flight response. The parasympathetic nervous system controls the body's ability to relax.

Answer 154

The enteric nervous system (ENS) is large, complex and uniquely able to orchestrate gastrointestinal behaviour independently of the central nervous system (CNS). An intact ENS is essential for life and ENS dysfunction is often linked to digestive disorders

Answer 155

PNS consists of autonomic and somatic nervous system generally operates without conscious thought to regulate visceral function and maintain homeostasis e.g. heart rate, temperature, breathing etc.

Answer 156

spinal nerves + (most) cranial nerves *somatic (afferent-sensory/efferent-motor) and autonomic (sympathetic/parasympathetic)

Answer 157

conscious/voluntary control self regulating/involuntary control

Answer 158

enteric nervous system often referred to as 'second brain' approx. 600 million neurons located in walls of the GI tract as 2 plexi. influenced by sympathetic and parasympathetic input, hormones and sensory input. can act autonomously to control peristalsis and secretion.

Answer 159

approx. 600 million neurons located in walls of the GI tract as 2 plexi

Answer 160

enteric nervous system is influences by sympathetic and parasympathetic input, hormones and sensory input. *can act autonomously to control peristalsis and secretion

Answer 161

autonomic pathways consist of 2 neurons which synapse in a ganglion; 2 neuron efferent pathway

Answer 162

parasympathetic= acetylcholine sympathetic= noradrenaline

Answer 163

somatic= skeletal muscle autonomic= smooth muscle, cardiac muscle and glands

Answer 164

somatic= conscious and unconscious movement autonomic= unconscious regulation for homeostasis (mostly)

Answer 165

somatic= one from CNS to skeletal muscle autonomic= 2: preganglionic from CNS to autonomic ganglion and postganglionic from ganglion to target tissue

Answer 166

1. preganglionic- from CNS to autonomic ganglion 2. postganglionic- from ganglion to target tissue

Answer 167

somatic= myelinated autonomic= preganglionic (myelinated), postganglionic (unmyelinated)

Answer 168

preganglionic= myelinated postganglionic= unmyelinated

Answer 169

somatic= acetylcholine (ACh) autonomic - preganglionic= acetylcholine (ACh) - postganglionic= noradrenaline/acetylcholine

Answer 170

preganglionic = acetylcholine (ACh) postganglionic= noradrenaline/ACh

Answer 171

somatic= nicotinic in skeletal muscle autonomic= nicotinic in ganglia; muscarinic/adrenergeic in target tissue

Answer 172

ganglia= nicotinic target tissue= muscarinic/adrenergic

Answer 173

muscarinic or adrenergic

Answer 174

originate from: - cranial nerves (III, VII, IX, X) - spinal cord levels S2-S4 - craniosacral outflow

Answer 175

originate from: - spinal cord levels T1-L2 - specifically the lateral horn (intermediolateral nucleus) - thoracolumbar outflow The "lateral horn" refers to a specific area of gray matter in the spinal cord, primarily found in the thoracic and upper lumbar regions, containing the cell bodies of preganglionic sympathetic neurons

Answer 176

parasympathetic originate from: - cranial nerves (III, VII, IX, X)- 3, 7, 9, 10 - spinal cord levels S2-S4 - craniosacral outflow sympathetic originate from: - spinal cord levels T1-L2 - specifically the lateral horn (intermediolateral nucleus) - thoracolumbar outflow

Answer 177

parasympathetic: - cranial nerves III, VII, IX synapse in ganglia in the head - cranial nerve X and sacral neurons synapse in ganglia close to the target organ sympathetic - sympathetic chain - prevertebral (pre-aortic) ganglia *Sympathetic ganglia are located close to the spinal cord, forming the sympathetic chain, while parasympathetic ganglia are situated near or within the organs they innervate (X); 3, 7, 9 synapse in head

Answer 178

*long preganglionic neurons and short post ganglionic neurons- ganglia are close to the organs parasympathetic only has visceral (organ) distribution.

Answer 179

the sympathetic chain is a series of ganglia that extend from cranial base to coccyx also called sympathetic trunks or the paravertebral ganglia help distribute the sympathetic neurons throughout the body

Answer 180

1. sympathetic trunks 2. paravertebral ganglia the sympathetic chain is a series of ganglia that extend from cranial base to the coccyx

Answer 181

The coccyx, commonly known as the tailbone, is the small, triangular bone located at the base of the spine, formed by fused vertebrae, and serves as an attachment point for muscles and ligaments of the pelvic floor. the final segment of the vertebral column, or spine

Answer 182

not all organs receive dual innervation from sympathetic and parasympathetic divisions e.g. blood vessels only sympathetic

Answer 183

sympathetic and parasympathetic divisions often have opposing actions on an organ but not always e.g. salivary glands (work together to alter composition)

Answer 184

both divisions are always active to maintain homeostasis- can tip balance towards more parasympathetic/less sympathetic activity vice versa

Answer 185

Cardiac muscle: Acetylcholine via M2 receptors leads to a reduction in heart rate and contraction strength. *muscarinic receptors Smooth muscle: Acetylcholine via M3 receptors increases intracellular calcium and promotes contraction. *muscarinic M3 receptor. The parasympathetic nervous system influences various tissues in the body through its postganglionic neurons, which release acetylcholine (ACh) as the primary neurotransmitter. The effects on different tissues can be quite different due to variations in the types of receptors found on the target cells and how these receptors interact with the signaling pathways.

Answer 186

G protein-coupled receptors G protein-coupled receptors (GPCRs) are integral membrane proteins containing an extracellular amino terminus, seven transmembrane α-helical domains, and an intracellular carboxy terminus. GPCRs recognize a wide variety of signals ranging from photons to ions, proteins, neurotransmitters, and hormones.

Answer 187

the type 2nd messenger system triggered in the cell determines whether its function is activated or inhibited

Answer 188

1. M1 (central nervous system) 2. M2 (heart-SA node, AV node, atria) 3. M3 (smooth muscle, glands)

Answer 189

1. α1 (smooth muscle- blood vessels, GI tract sphincters, bladder sphincters, eye) 2. α2 (smooth muscle- blood vessels, GI tract) 3. β1 (heart- SA node, AV node, ventricles; kidney) 4. β2 (smooth muscle- blood vessels, bronchioles, GI tract, bladder wall, uterus) cell surface proteins that bind to the neurotransmitters and hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), playing a crucial role in the sympathetic nervous system's response to stress and other physiological events

Answer 190

The limbic system is a group of structures in your brain that regulate your emotions, behaviour, motivation and memory

Answer 191

sensory and motor cortex and the limbic system --> hypothalamus hypothalamus-> brainstem ANS centres -> increase/decrease sympathetic/parasympathetic activity visceral afferents-> nucleus tractus solitarius (NTS)-> brainstem ANS centres NTS-> hypothalamus The central control of the ANS is governed by a network of connections starting from the sensory and motor cortex and the limbic system (which process emotions and sensory information), which then send signals to the hypothalamus. The hypothalamus directs the brainstem ANS centers, which regulate sympathetic and parasympathetic activity. Additionally, visceral afferents provide sensory input to the NTS, which then influences the brainstem and the hypothalamus to ensure proper autonomic regulation.

Answer 192

The hypothalamus is a structure deep within your brain. It's the main link between your endocrine system and your nervous system. Your hypothalamus keeps your body balanced in a stable state called homeostasis. The hypothalamus is an area of the brain that produces hormones that control: Body temperature. Heart rate. Hunger.

Answer 193

The baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels. The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure causes the heart rate to decrease.

Answer 194

homeostasis (ANS reflexes maintain homeostasis e.g. baroreflex)

Answer 195

preganglionic sympathetic neurons synapse directly onto cells in the adrenal medulla adrenal medulla is essentially and modified sympathetic ganglion it is composed of specialised neuroendocrine cells which secrete noradrenaline and adrenaline directly into the blood stream 75-80% of the secretory output is adrenaline the inner part of the adrenal gland, responsible for producing catecholamines like epinephrine (adrenaline) and norepinephrine (noradrenaline), which are crucial for the body's "fight-or-flight" response

Answer 196

it is composed of specialised neuroendocrine cells which secrete noradrenaline and adrenaline directly into the blood stream

Answer 197

adrenal secretions act on adrenergic directly and globally this activates organs supplied by postganglionic sympathetic neurons e.g. blood vessels, liver, bronchi, pupil also acts on adrenergic receptors of other organs e.g. skeletal muscle to increase metabolism effect of adrenal medulla secretions last longer than direct synapses- blood stream does not contain enzymes to break down adrenaline and noradrenaline

Answer 198

bloodstream does not contain enzymes to break down adrenaline and noradrenaline

Answer 199

adrenal secretions act on adrenergic receptors directly and globally this activates organs supplied by postganglionic sympathetic neurons e.g. blood vessels, liver, bronchi, pupil also acts on adrenergic receptors of other organs e.g. skeletal muscle to increase metabolism

Answer 200

The adrenal medulla, the inner part of an adrenal gland, controls hormones that initiate the flight or fight response. The main hormones secreted by the adrenal medulla include epinephrine (adrenaline) and norepinephrine (noradrenaline), which have similar functions.

Answer 201

due to its widespread distribution and importance in maintaining homeostasis, the ANS is implicated in the mechanisms underlying many different conditions e.g. hypertension, heart failure, obesity, depression, chronic pain, inflammation, alzheimers disease, polycystic ovary syndrome, obstructive sleep apnoea

Answer 202

muscarinic antagonists e.g. atropine (belladonna/deadly nightshade) - used in surgery to prevent parasympathetic reflexes when handling organs - used recreationally in past as eye drops to dilate pupils beta-adrenergic antagonists (beta-blockers) e.g. propranolol - slows heart rate preventing arrhythmias beta-adrenergic agonists e.g. salbutamol - promotes bronchodilation to prevent asthma [an agonist activates a receptor, while an antagonist blocks or inhibits the action of the receptor, preventing a biological response]

Answer 203

beta-adrenergic agonist e.g. salbutamol - promotes bronchodilation to relieve asthma

Answer 204

beta-adrenergic antagonists (beta blockers) e.g. propranolol - slows heart rate preventing arrhythmias *An arrhythmia, or irregular heartbeat, is a problem with the rate or rhythm of your heartbeat. Your heart may beat too quickly, too slowly, or with an irregular rhythm.

Answer 205

muscarinic antagonists e.g. atropine (belladonna/deadly nightshade) *an antagonist blocks or inhibits the action of the receptor

Answer 206

It is composed of three sections in descending order: the midbrain, pons, and medulla oblongata. It is responsible for many vital functions of life, such as breathing, consciousness, blood pressure, heart rate, and sleep. The brainstem contains many critical collections of white and grey matter.

Answer 207

Saltatory conduction is the rapid method by which nerve impulses move down a myelinated axon with excitation occurring only at nodes of Ranvier

Answer 208

Broca's area, located in the left hemisphere, is associated with speech production and articulation. Our ability to articulate ideas, as well as use words accurately in spoken and written language, has been attributed to this crucial area. a type of aphasia characterized by partial loss of the ability to produce language (spoken, manual, or written), although comprehension generally remains intact. A person with expressive aphasia will exhibit effortful speech.

Answer 209

Your cerebral cortex is the outer layer that lies on top of your cerebrum. Your cerebrum is the largest area of your brain. Your cerebrum divides your brain into two halves called hemispheres. The hemispheres are attached by a bundle of nerve fibres called the corpus callosum.

Answer 210

After an action potential, there's a brief refractory period where the neuron can't fire another action potential immediately. This ensures that the signal only moves in one direction down the axon.

Answer 211

Alpha motor neurons (also called lower motor neurons) innervate skeletal muscle and cause the muscle contractions that generate movement. Motor neurons release the neurotransmitter acetylcholine at a synapse called the neuromuscular junction.

Answer 212

from the Achilles tendon (where the reflex is elicited) to the sensory-motor synapse in the spinal cord (S1 level) and back again

Answer 213

the complexity of the cognitive processes involved in stimulus identification, decision-making, and motor planning

Answer 214

Jendrassik maneuver primarily enhances reflex amplitude, studies suggest it can also shorten the latency of the knee reflex, although the Achilles tendon reflex latency may not be significantly altered

Answer 215

latency refers to the time delay between a stimulus and the onset of the reflex response, while amplitude refers to the magnitude or strength of the reflex response.

Answer 216

Jendrassik maneuver is primarily known for enhancing reflex amplitude studies suggest it does not consistently increase conduction velocity in all subjects, *assesses the speed of electrical impulses through nerves

Answer 217

the dorsal root carries sensory (afferent) information towards the central nervous system, while the ventral root carries motor (efferent) information away from it. *dorsal" refers to the back or posterior side of the body, while "ventral" refers to the front or anterior side,

Answer 218

the placement of the ground/earth electrode can significantly contribute to EMG artifacts during reflex recordings, as improper grounding can lead to noise and interference in the recorded signals.

Answer 219

The intermediolateral nucleus (IML) is a group of autonomic motor neurons located in the lateral horn of the spinal cord, specifically in Rexed lamina VII, extending from the first thoracic to the second or third lumbar spinal segments (T1-L2/L3), and is responsible for the entire sympathetic innervation of the body

Answer 220

The 10th cranial nerve is the vagus nerve (CN X), a mixed nerve that plays a crucial role in the parasympathetic nervous system, regulating various bodily functions like heart rate, breathing, and digestion

Answer 221

Sensory and motor cortex, limbic system, hypothalamus, brainstem

Answer 222

It sends signals to the hypothalamus, which helps in regulating autonomic functions such as heart rate, blood pressure, and temperature.

Answer 223

The hypothalamus regulates autonomic functions by modulating the brainstem ANS centers, affecting sympathetic and parasympathetic activity.

Answer 224

The NTS receives sensory input from visceral afferents and relays the information to the brainstem ANS centers to adjust autonomic functions.

Answer 225

Visceral afferents send sensory signals from internal organs to the NTS, which then modulates autonomic responses through the brainstem and hypothalamus.

Answer 226

The NTS sends signals back to the hypothalamus, allowing for adjustments in autonomic regulation based on sensory input from internal organs.

Answer 227

In the autonomic nervous system, preganglionic neurons originate in the brainstem or spinal cord and their axons synapse in a ganglion with postganglionic neurons. Preganglionic neurons are typically shorter, release acetylcholine, and synapse in ganglia near the target organs in the parasympathetic system or closer to the spinal cord in the sympathetic system. Postganglionic neurons, on the other hand, are generally longer, release norepinephrine in the sympathetic system and acetylcholine in the parasympathetic system, and their axons extend to the target organ