INTS 6: Introduction to Nervous and Musculoskeletal Systems Flashcards

1
Q

What is the nervous system?

A
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2
Q

What is the nervous system comprised of?

Very briefly describe their function

A
  • central nervous system (CNS) :
  • brain
  • spinal cord
  • peripheral nervous system (PNS) :
  • cranial peripheral nerves
  • spinal peripheral nerves
  • these help carry out sensory and motor functions
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3
Q

Where do cranial nerves arise from?

A
  • the brain and brainstem
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4
Q

Where do spinal nerves arise from?

A
  • the spinal cord
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5
Q

What type of neurons are most cranial and all spinal nerves made up of?

A
  • they are made up of axons of both motor and sensory neurons
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6
Q

What pathways does the PNS use to send/relay information?

A
  • relaying information back to CNS:
  • sensory/afferent/ascending pathways
  • sending information from CNS to the rest of the body:
  • motor/efferent/descending pathways
  • motor pathways can be further divided into somatic (voluntary) and autonomic (involuntary) components
  • observe diagram
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7
Q

Observe the diagram and define these orientation terms

A
  • ventral and dorsal change along the course of the nervous system
  • rostral:
  • anything toward the anterior pole of the brain
  • caudal:
  • anything toward the inferior pole of the spinal cord
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8
Q

Observe this diagram of the different planes of orientation

A
  • this will be further explained in later sessions
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9
Q

What is the part of the CNS housed within the cranial cavity called?

A
  • the brain
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10
Q

Describe the surface features of the brain

A
  • ridges: called gyri
  • grooves: called sulci
  • larger grooves: called fissues
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11
Q

Describe the divisions of the brain

A
  • comprised of the forebrain:
  • cerebral hemispheres
  • hypothalamus
  • thalamus
  • midbrain
  • hindbrain:
  • pons
  • medulla
  • cerebellum
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12
Q

Describe the lobes the cerebral hemispheres are divided into

A
  • frontal
  • parietal
  • occipital
  • temporal
  • limbic
  • insular
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13
Q

How much of the body’s blood supply does the brain receive?

Compare it to the weight

A
  • 15-20 of the body’s blood supply
  • whereas it’s 2% of total body weight
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14
Q

Which two principal sources supply blood to the brain?

Where is the source of these sources?

A
  • internal carotid arteries
  • vertebral arteries
  • these arteries are indirect or direct branches of the main artery from the heart, the aorta
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15
Q

Describe the Circle of Willis

How do the internal carotid and vertebral arteries supply blood to the brain?

A
  • The internal carotid arteries ascend in the neck and enter the cranial cavity through holes (foramina) in the skull
  • The vertebral arteries, as the name suggests, are associated with the bones in the neck, the vertebrae
  • The two vertebral arteries join to form the basilar artery, this vertebral-basilar system supplies the brainstem and spinal cord.
  • The forebrain receives blood from both the internal carotid and vertebral-basilar systems, which join to form an arterial circle at the base of the brain - the Circle of Willis.
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16
Q

Where do the anterior, middle and posterior cerebral arteries supply?

A
  • The anterior cerebral arteries:
  • supply the medial surfaces of the front two thirds of the cerebral hemispheres
  • the middle cerebral arteries (extensions of the internal carotid arteries):
  • supply most of the lateral surfaces of the brain as well as deep structures
  • the posterior cerebral arteries:
  • supply the medial surfaces of the posterior one third of the forebrain
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17
Q

What subdivisions form the autonomic nervous system?

A
  • parasympathetic:
  • rest and digest
  • under ‘normal’ circumstances
  • sympathetic:
  • fight or flight
  • when are body is put into a stressful situation
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18
Q

What are some responses from

  • parasympathetic system
  • sympathetic
A
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19
Q

What do sensory neurons do?

A
  • relay information toward the CNS
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20
Q

What do motor neurons do?

A
  • relay information away from the CNS
21
Q

What types of axons do peripheral nerves carry?

A
  • most peripheral nerves carry a mixture of sensory and motor axons
22
Q

What is a ganglion?

A
  • a cluster of neuronal cell bodies
23
Q

Where do cell bodies of sensory neurons reside?

A
  • within the dorsal root ganglia
24
Q

Where do the cell bodies of motor neurons reside?

A
  • within the ventral horn of the spinal cord
  • or within the brain
25
Q

What are pre-ganglionic neurons?

A
  • neurons with axons which run from the spinal cord or brain to a ganglion
26
Q

What are post-ganglionic neurons?

A
  • neurons with axons which run from a ganglion to their destination
27
Q

Where are the pre-ganglionic neurons of the sympathetic and parasympathetic division located?

A
  • sympathetic pre-ganglionic neurons:
  • located in the lateral horn of the spinal cord found only in the thoracolumbar region (T1-L2/3)
  • parasympathetic:
  • located within the brainstem and the sacral region of the spinal cord
28
Q

What is the function of these structures in a neuron?

  • dendrites
  • cell body
  • axon
  • axon terminals
A
  • dendrites:
  • receive inputs
  • cell body:
  • receives and sums imputs
  • axon:
  • sends inputs to other nerve cells
  • axon terminals:
  • contact dendrites of other neurons
29
Q

What part of the neurons provide insulation in:

  • the PNS
  • CNS
A
  • in PNS:
  • Schwann cells:
  • contain myelin, surround the axon
  • in CNS:
  • oligodendrocytes
30
Q

What are the unmyelinated spaces of neuron called?

A
  • nodes of Ranvier
31
Q

What are the three types of neuron?

A
  • multipolar
  • pseudounipolar
  • bipolar
32
Q

Describe the chracteristics of multipolar neurons

A
  • the most abundant neuronal type
  • found in the brian and spinal cord
  • have multiple dendrites attached to the cell body (soma) and a single azon arising from the axon hillock
33
Q

Describe the chracteristics of pseudounipolar neurons

A
  • found mainly in spinal ganglia and receive sensory information from the periphery
  • The signal travels along a dendritic axon to the axon, bypassing the cell body
34
Q

Describe the characteristics of bipolar neurons

A
  • found in the retina and in olfactory epithelium
  • Like the pseudopolar neurons, they have a dendritic axon which conveys information to the axon via the cell body
35
Q

How many times do glial cells outnumber neurons?

A
  • 10:1
36
Q

What are the different types of glial cells and their functions?

A
  • Microglia:
  • play an important role in immune function within the CNS.
  • Astrocytes:
  • perform a number of supportive functions in the CNS.
  • Oligodendrocytes:
  • create the myelin sheath surrounding axons in the CNS.
  • Schwann cells:
  • create the myelin sheath surrounding some axons in the PNS.
  • Ependymal cells:
  • line the ventricular system and separate the cerebrospinal fluid from the neural tissue.
  • Polydendrocytes:
  • are stem cells within the brain which can generate both glial cells and neurons.
37
Q

What are the two ways communication occurs between neurons at synapses?

A
  • electrical:
  • ions move directly between neurons at gap junctions
  • chemical:
  • neurotransmitters convey the signal from one neuron to another
38
Q

What are the main types of synapses?

A
  • Axodendritic:
  • these are the most common form of synapse
  • The dendritic tree of the neuron receives many thousands of inputs from axons
  • The organisation and function of the dendritic tree determines the convergence of signals.
  • Axosomatic:
  • the axon of one neuron can connect to the soma of the post-synaptic neuron
  • Less common than axodendritic synapses.
  • Axoaxonic:
  • the axon of one neuron connects at or near to the axon hillock of the post-synaptic neuron.
39
Q

What is the skeleton made up of?

A
  • the bones
  • cartilage
40
Q

What do muscles consist of?

A
  • muscle fibres
  • blood vessels
  • nerve fibres
  • connective tissue
41
Q

What are the six major functions of the musculoskeletal system?

A
  • producing movement
  • maintaining posture
  • stabilising joints
  • producing heat
  • protection:
  • hard bone tissue defends soft organs from damage
  • mineral storage:
  • bones are a repository of key minerals:
  • calcium, phosphorus, sodium, magnesium
42
Q

What are the two major types of muscle?

A
  • striated muscle:
  • separated into:
  • skeletal
  • cardiac
  • smooth muscle
43
Q

Briefly describe the function and structure of skeletal muscle

A
  • attach two or more bones
  • facilitate movement at a joint
  • it is striated
  • it is under voluntary control
44
Q

Briefly describe the structure, location and function of smooth muscle

A
  • found in the walls of blood vessels, the digestive, urinary, respiratory and reproductive systems
  • Smooth muscle pushes substances through these organs, e.g. smooth muscle in the walls of blood vessels pushes blood around the body
  • The muscle tissue does not have striations, like skeletal and cardiac muscle, hence the name ‘smooth’ muscle.
  • The contractions of smooth muscle fibres are slow and sustained.
  • Smooth muscle is not under voluntary control.
45
Q

Briefly describe the structure and function of cardiac muscle

A
  • present in the heart and is responsible for the continued beating of the heart throughout life
  • cardiac muscle is striated, like skeletal muscle
  • but is not under voluntary control
46
Q

Explain the properties of muscles

A
  • excitability:
  • Muscle tissue receives chemical stimulation from the nervous system
  • This results in generation of an electrical impulse that travels around the muscle fibres and causes them to contract
  • contractility:
  • refers to the muscle’s ability to shorten following stimulation
  • It is important to note that while muscle contraction can result in muscle shortening, muscle contraction does not necessarily result in a net change in muscle length
  • extensibility:
  • refers to the ability of muscle fibres to be stretched or extended, when they are relaxed.
  • This is necessary to allow opposing movements at joints.
  • For example, if a muscle crossing the front of a joint is shortening to produce a movement, then the muscle crossing the back of the joint must be able to be stretched.
  • elasticity:
  • reflects the requirement for a muscle to recoil to its resting length after being stretched
47
Q

What are the characteristics of the bones and cartilage?

  • yellow is bone
  • blue is cartilage
A
  • bone tissue:
  • rigid
  • hard to break
  • cartilage:
  • provides cushioning
  • support the bones of the skeleton
48
Q

What causes movement?

A
  • the muscles attached to the skeleton allow us to move
  • muscles attach to bones across joints
  • factors that influence range of movement:
  • shape of the bones at the joints
  • location of the muscle attachments
  • size of muscle