Module 5- large body systems Flashcards
Threshold of an Action Potential
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Steps of an Action Potential
- resting state is disturbed and starts to depolarize
- Threshold is reached and voltage gated ion channels open, Na+ flow into the cell making it even more positive
- The peak of the AP is reached when the cell can’t take anymore positive charged molecules
- K+ Voltage gated ion channels open to try and depolarize the cell
- There is a small period when the cell becomes too negative before returning to its rest state (Na+/K+ pumps work in the background to reset the concentration gradient)
Schwann cells
produce myelin sheets for faster action potential travel
Absolute Refractory period
the time period when an action potential cannot be fired
Synaptic integration
summation of all EPSPs and IPSPs
Spatial Summation
Sum of all EPSPs and IPSPs received on a neuron at different synapse locations
Temporal Summation
Summation of either all the EPSPs or IPSPs received from a singular synapse within a short time frame
Skeletal Muscles
- Cover the skeleton
- Voluntary movements
- Range of Motion is usually dominated by the skeletal system
Origin
Proximal muscle anchoring attachment
Insertion
Distal muscle attachment connected to the moving bone
Tendons
Connection of muscle to bone
What make up Muscle Fibers
actin and myosin
Motor Unit
The group of fibers one neuron controls
Fascia
Sheet of tissue that makes up the outer layer the muscle
Fascicles
Bundles of muscle fibers
Myofibrils
Bundles of contractile proteins
Sarcomere
The band that spans the length of the myosin and actin proteins
Z disks
anchor the actin filaments
M band
Anchor the Myosin filaments
Cross bridges
Connections between actin and myosin that result in contraction of muscle fibers
Troponin
Holds the Tropomyosin in place to prevent a cross bridge and thus muscle contraction
Muscle contraction
shortening of the sarcomere
Neuromuscular junctions
The connection between the synapse and the myofibrils
how to cause a contraction from neuron to actin
- an AP is sent down the neuron
- the AP starts the release of acetylcholine to the myofibril
- AP travels down the t-tubule to start the release of Ca+
- Ca+ bind to the troponin which release the tropomyosin
- with the use of ADP-Pi, myosin are able form cross bridges and contract the actin when it becomes ADP
Tetany
The sum of many twitches spaced closely together
Recruitment
The body will activate the motor units that give off the least max strength first and work its way up will it has to use all the motor units at once
Innervation ratio
the actual number of muscle fibers controlled by one neuron
Slow twitch fibers
- benefits small force production of energy for a longer period of time
- activated first
Fast twitch fibers
- large force generated over a short period of time
- Fatigue easily
- recruited when needed
Atrophy
Decrease in size due to lack of use
Force
Alters an objects motion or distorts it (Newtons)
Force equation
Mass x Acceleration
Net Force
Sum of all forces acting on the object
Static State
all forces cancel out and result in no movement
Dynamic state
Forces are unequal and results in movement
Stress
Force focused on at one area
Stress equation
stress = Force/ Area
Tension
Pulling force
Compression
Pressing force
object Tension/ compression laws
The force decreases as you look closer to the neutral axis
Stiffness
The ability to resist being deformed
Work
The effort it takes to deform or break an object
Failure
Object breaks
Elastic deformation
Object can deform but return to its previous state
Plastic deformation
Permanently change the objects shape
Hydrostat (Plant)
- membrane pushes back onto the fluid making it rigid
- ## allows plants to resist gravity
Hemi-cellulose (Plant)
- Elastic
- Resist tension
Cellulose (Plant)
- stiff
- tensile strength
- primary and secondary cell walls
Plant cell growth
Cell can only expand parallel to the cellulose fiber
Elastin (animal)
- makes the membrane elastic
Collagen
- makes a rigid membrane
Vertebrates Hydrostats
- coelomic cavities
- Intervertebral disks
Muscular Hydrostats
- muscles hold water within
- Circular muscles around
- longitudinal muscles
Circular muscles
- elongates the muscle
Longitudinal Muscles
- Shortens the muscle
Hydrostat failure
Increase stress on body walls without sufficient stiffness leads to failure
Composite materials
a combination of materials to get the best of both
Xylem
- dead plant cells that pack closed together towards the surface of the plant (Secondary cell wall)
- Transports water, and minerals
Stiffness of a tube vs a rod
A tube will have more stiffness because the greatest amount of material is the farthest from the neutral axis
Lignin
- Resists compression
- Aids in fluid
- Secondary cell wall
Open Exoskeleton
- composite shell
-doesn’t fully enclose the body - Can open and close portions
- anchor points for muscles
Brittle
- can withstand heavy loads with little deforming
- Stiff/ will break
Closed exoskeleton
- Composite material: chitin
- Rigid external shell
- Flexible areas between rigid plates
- limits growth
- Ecdysis
Ecdysis
molting, allows for growth
Metazoan Endoskeleton
Echinoderms:
- mutable connective tissue- controlled stiffness
- Tubed feet become hydrostats
Vertebrates:
- Composite material
- Connective tissues: Bone
Parts of the Lever System
Fulcrum: joint
In-lever: from the point of the force to the fulcrum L(in)
out-lever: from the fulcrum to end of the movable system L(out)
Energy
Energy = Force X Length
Energy(in) = Energy(out)
L(in)/L(out) = F(out)/F(in)
-smaller value (High speed and ROM, Low force)
- Larger Value (Low speed and ROM, Force)
