Lecture 4: Muscular/Nervous Tissue Flashcards
what cells “use energy from ATP hydrolysis to generate force?”
muscle cells/myocytes/fibres
what contraction of muscle tissue produces
- body movement
- posture
- heat
types of muscle tissue
- skeletal muscle
- cardiac muscle
- smooth muscle
Is skeletal muscle controlled voluntarily or involuntarily?
voluntarily
what type of muscle tissue has the function for “movement; posture; heat; protection)
skeletal muscle
location of skeletal muscle
attached to bones by tendons
x3 structural aspects of skeletal muscle
- appear striated
- cylindrical fibres
- multinucleate
smallest skeletal muscle
stapedius muscle
true or false,
“the strapedius provides
Stability of smallest human bone (stapes) in ear
Modify intensity of sound that’s transmitted through to our hearing
Prevent hyperacusis; tympanic reflex; Bell’s Palsy”
true
largest skeletal muscle
sartorius
true or false
“the sartorius acts as the hip and knee flexor”
false
“the sartorius functions as a…
Hip: flexor, lateral rotator, abductor
Knee: flexor”
what causes the striations in the myocytes/muscle cells?
highly organised arrangement of myofibrils in cells
what component of a myocyte are
“striped tubular structures extending length of the cell”
myofibrils
inside the myofibrils what component makes the striation lines?
myofilaments
the myofibrils are composed of x2 types of myofilaments, thick and thin
what are each thick and thin filament made of?
thin filament = actin
thick filament = myosin
the grouped/segmented arrangement of _____ are called _____. These DO NOT extend length of muscle cell
the grouped/segmented arrangement of (myofilaments) are called (sarcomeres). there DO NOT extend length of the muscle cell
true or false
“the filaments overlap to produce striations in myofibril”
true
describe function of each…
A band; I band ; H zone; M line; Z disc; titin
A band = Distance between 2 ends of thick filaments
I band = spans end of thick filament > Z line > next sarcomere
H zone = middle; no overlap of thick/thin filaments
M line = middle of sarcomere to hold thick filaments together
Z disc = pass through centre of I band
Titin = provide resting tension in I band, molecular spring
what component is a contractile and functional unit of a myofibril?
sarcomere
true or false
“Z discs separate sarcomeres”
true
name the x5 CT components of skeletal muscle from largest to smallest
- epimysium
- perimysium
- endomysium
- sarcolemma
- sarcoplasm
function of the epimysium
surrounds entire muscle
- allow for separate function
function of the perimysium
surrounds the fascicles
function of the endomysium
surrounds muscle cells
function of the sarcolemma
cell plasma membane
what is the sarcoplasm
muscle cell cytoplasm
true or false
“the heart needs to contract in uniform/controlled way and generate force”
true
is the cardiac muscle control involuntary or voluntary?
involuntary
x3 structural features of the cardiac muscle
- striated + branched
- single central nucleus
- fibres join end-to-end through intercalated discs
what x2 components do intercalated discs contain
- desmosomes
- gap junctions
function of desmosomes in intercalated discs
Adhesion junctions anchor cell membranes to intermediate filament in contraction
true or false
“gap junctions in intercalated discs form communication between cells via electrical impulses to co-ordinate and perform rapid conduction”
true
what are “specialised muscle cells that conduct electrical activity around the heart”
purkinje fibres
do smooth muscle contain striations?
NO
locations where…
1. smooth muscle has gap junctions
2. smooth muscle NO gap junctions
- gut
- iris
x5 possible locations where smooth muscle is found
- Intestines = peristalsis
- Blood vessel walls = constriction
- Iris of eye
- Reproductive; urinary; digestive; respiratory systems
- Skin erector pili
what type of muscle are these structural components from?
i. Short, small, spindle shape… thickest in middle
ii. No striations
iii. Single, central nucleus
smooth muscle
what happens to cell during contraction of smooth muscle
shrinks + twists
x2 subdivisions + components of the nervous system
- CNS: spine, brain, optic nerve
- PNS: all nervous tissue outside of the CNS
x2 subdivisions + function of the PNS
- sensory/afferent division: info to CNS
- motor/efferent division: info from CNS to organs (muscles + glands)
the nervous system helps to…
- maintain _____
- initiate _____ movement
- high functions _____, _____, _____
the nervous system helps to…
- maintain (homeostasis)
- initiate (voluntary) movement
- high functions (perception), (behaviour), (memory)
what are the x3 major functions activities of the nervous system activities are grouped in
- sensory
- integrative
- motor
what major function of sensory; integrative; motor carry out…
“info collection; detection of internal/external stimuli and transfer to CNS”
sensory
what is function of integrative function
Take info and use it for something; analysis and storing of info
what is the function of integrative function
Take info and use it for something; analysis and storing of info
what is the function of motor functions
Action; stimulation of effectors (muscle and glands) through PNS
x2 types of nerve cells
- neurons
- neuroglia
true or false,
neurons are large nerve cells that function to “conscious and unconscious control”
true
what type of nerve cell
“supportive cells - small
(collective term for lots of different types of cells)”
neuroglia
X3 structure features of neurons
- short cell body
- branched dendrites for nerve impulses (action potentials)
- single axon for conducting nerve impulses to another neuron/tissue
x2 Neuron structural components + function
- Dendrites = receive/input part of neuron
- Axon = carry nerve impulse away from neuron
true or false
neurons divide and have a low metabolic rate
FALSE
Neurons
- DO NOT divide
- High metabolic rate (glucose)
structure and function of MULTIPOLAR neurons
I. Have 2 or more dendrites + single axon
II. Most common neurons in CNS
III. All motor neurons (control skeletal muscle) are in this class
IV. Some of longest (spinal cord > toe muscles)
structure and function of BIPOLAR neurons
I. X2 processes (1 dendritic process + 1 axon)
II. Cell body between axon and dendrite
III. Rare + small
IV. Special sense organs relay info from receptor > neurons
structure and function of UNIPOLAR neurons
I. Dendrites and axon continuous
II. Cell body off to one side
Can go from dendrites > axon
III. Whole thing from where dendrites converge called axon
IV. Most sensory nerves are unipolar
V. Very long; like motor nerves: CNS > toe top
structure and function of ANAXONIC neurons
I. Rare + function poorly understood
II. Anatomy cannot distinguish dendrites from axons
III. Found in brain + special sense organs
are these features part of neurons or neuroglia?
- Found in CNS and PNS
- Smaller than neurons/more numerous
- Do NOT propagate action potentials… chemical communicate
- Can DIVIDE within mature nervous system
(Damage to brain; neuroglia will line area of damage)
neuroglia
x5 functions of the neuroglia
- Physical structure of nervous tissue; substance of nervous system
- Repair framework of nervous tissue
- Phagocytosis; gobble up debris and bacteria
- Maintain nutrient supply to/around neurons
- Regulate interstitial fluid in neural tissue
CNS neuroglia classifications (x4)
- astrocytes
- oligodendrocytes
- microglia
- ependymal cells
Structures and functions of astrocytes
a) Star shaped; largest; most numerous of neuroglia Syncytium network
b) Support (contain microfilaments) + repair (scar)
c) Communicate with neurons via ‘gliotransmitters’ (eg. glutanmate)
d) Maintain environment around neuron (eg. Regulate ions)
e) Maintain blood-brain barrier via endothelium.
structure and function of oligodendrocytes
a) Form insulating multi-layered myelin sheath (protein lipid layer) around CNS axons
b) Can myelinate more than 1 neuron cell’s axon; connection between neuron axon’s.
Accelerate action potential
structure and function of microglia
Protection: Phagocytic (resident macrophages)
structure and function of ependymal cells
a) Produce cerebrospinal fluid (CSF)
b) Line CSF – filled ventricles in brain and central canal of spinal cord
c) Single layer of cuboidal cells have cilia – flow of CSF around the brain – and microvilli – SA for sampling CSF for modifications
d) Located in ventricles and other CSF locations
e) CSF mechanical buffer: moves nutrients + waste
PNS neuroglia classifications (x2)
Schwann cells
Satellite cells
structure and function of Schwann cells
equiv. to CNS oligodendrocyte
Form insulating myelin sheath around axons
Support around several non-myelinated axons
- x1 schwann cell per axon for myelination but more axons/cell if just support
structure and function of satellite cells
equiv. to astrocytes in CNS
a) Surround neuron cell bodies
b) Support + fluid exchange
