INTS 6: Introduction to Nervous and Musculoskeletal Systems Flashcards
(48 cards)
1
Q
What is the nervous system?
A
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
3
Q
Where do cranial nerves arise from?
A
- the brain and brainstem
4
Q
Where do spinal nerves arise from?
A
- the spinal cord
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
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
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
8
Q
Observe this diagram of the different planes of orientation
A
- this will be further explained in later sessions
9
Q
What is the part of the CNS housed within the cranial cavity called?
A
- the brain
10
Q
Describe the surface features of the brain
A
- ridges: called gyri
- grooves: called sulci
- larger grooves: called fissues
11
Q
Describe the divisions of the brain
A
- comprised of the forebrain:
- cerebral hemispheres
- hypothalamus
- thalamus
- midbrain
- hindbrain:
- pons
- medulla
- cerebellum
12
Q
Describe the lobes the cerebral hemispheres are divided into
A
- frontal
- parietal
- occipital
- temporal
- limbic
- insular
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
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
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.
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
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
18
Q
What are some responses from
- parasympathetic system
- sympathetic
A
19
Q
What do sensory neurons do?
A
- relay information toward the CNS
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
What are pre-ganglionic neurons?
- neurons with axons which run from the spinal cord or brain to a ganglion
26
What are post-ganglionic neurons?
- neurons with axons which run from a ganglion to their destination
27
Where are the pre-ganglionic neurons of the sympathetic and parasympathetic division located?
- 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
What is the function of these structures in a neuron?
- dendrites
- cell body
- axon
- axon terminals
- dendrites:
- receive inputs
- cell body:
- receives and sums imputs
- axon:
- sends inputs to other nerve cells
- axon terminals:
- contact dendrites of other neurons
29
What part of the neurons provide insulation in:
- the PNS
- CNS
- in PNS:
- Schwann cells:
- contain myelin, surround the axon
- in CNS:
- oligodendrocytes
30
What are the unmyelinated spaces of neuron called?
- nodes of Ranvier
31
What are the three types of neuron?
- multipolar
- pseudounipolar
- bipolar
32
Describe the chracteristics of multipolar neurons
- 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
Describe the chracteristics of pseudounipolar neurons
- 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
Describe the characteristics of bipolar neurons
- 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
How many times do glial cells outnumber neurons?
- 10:1
36
What are the different types of glial cells and their functions?
- 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
What are the two ways communication occurs between neurons at synapses?
- electrical:
- ions move directly between neurons at gap junctions
- chemical:
- neurotransmitters convey the signal from one neuron to another
38
What are the main types of synapses?
- 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
What is the skeleton made up of?
- the bones
- cartilage
40
What do muscles consist of?
- muscle fibres
- blood vessels
- nerve fibres
- connective tissue
41
What are the six major functions of the musculoskeletal system?
- 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
What are the two major types of muscle?
- striated muscle:
- separated into:
- skeletal
- cardiac
- smooth muscle
43
Briefly describe the function and structure of skeletal muscle
- attach two or more bones
- facilitate movement at a joint
- it is striated
- it is under voluntary control
44
Briefly describe the structure, location and function of smooth muscle
- 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
Briefly describe the structure and function of cardiac muscle
- 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
Explain the properties of muscles
- 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
What are the characteristics of the bones and cartilage?
- yellow is bone
- blue is cartilage
- bone tissue:
- rigid
- hard to break
- cartilage:
- provides cushioning
- support the bones of the skeleton
48
What causes movement?
- 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
