kinesiology lab assignment 2

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Principles of Kinesiology Lecture 02 Professor Berthet

Apparel Technical Design

Anatomical and Physiological

Fundamentals of Human Motion

The Musculoskeletal System:The Musculature System and its Movement

& The Neuromuscular Basis of

Human Movement (Ch. 3 & 4)

The Musculoskeletal System

! Extensibility and Elasticity: enable the muscle to be stretched and return to normal length. " Tendons are continuations of

muscle’s connective tissue and also possess these properties.

" Contractility: is the ability to shorten and produce tension.

Architecture of the Skeletal Muscle

Muscle Fiber

! Muscle Fiber: Consists of myofibrils held together by cell membranes that can propagate nerve impulses.

• Muscle • Muscle Fiber Bundle

• Muscle Fiber

Muscle

Muscle Fiber Bundle

Muscle Fiber: Myofibrils

! Myofibrils are arranged in parallel formation.

!Made up of alternating dark & light bands that give muscle fiber their striated appearance.

• Muscle • Muscle Fiber Bundle

• Muscle Fiber • Myofibrils

Actin: when stimulated slides over myosin.

Cross-bridges: projections (heads) of myosin attach to actin.

Functional contractile unit of skeletal muscle.

Muscle Fiber: Myofiliments

Myosin

“motor protein” perform cross-linking

Architecture of the Skeletal Muscle

Fast Twitch Muscles

! Fast twitch fibers are large, pale, and have less blood supply than slow twitch fibers.

"Suitable for intense responses over a short period of time

Slow Twitch Muscles

! Slow twitch fibers are small, red, and have a rich blood supply, and greater myoglobin (binds O2).

! Highly efficient, do not fatigue easily.

"Suitable for long duration, posture and endurance events.

Structural Classification of Muscles by Fiber Arrangement

! Longitudinal: long, strap like muscle with fibers in parallel to its long axis.

Structural Classification of Muscles by Fiber Arrangement

! Quadrilateral: four sided and usually flat.

! Consist of parallel fibers.

Structural Classification of Muscles by Fiber Arrangement

! Triangular: fibers radiate from a narrow attachment at one end to a broad attachment at the other.

" Pectoralis major

Structural Classification of Muscles by Fiber Arrangement

! Fusiform or Spindle-Shaped: rounded muscle that tapers at either end.

Structural Classification of Muscles by Fiber Arrangement

! Pennate: a series of short, parallel, feather like fibers extends diagonally from the side of a long tendon.

Structural Classification of Muscles by Fiber Arrangement

! Bipennate: A long central tendon with fibers extending diagonally in pairs from either side of the tendon.

Structural Classification of Muscles by Fiber Arrangement

! Multipennate: Several tendons are present, with fibers running diagonally between them.

! Middle deltoid

A

B

C

D

E

F

Longitudinal

Triangular

PCS ! Force a muscle can exert is

proportional to its physiological cross section (PCS).

! A broad, thick, longitudinal muscle exerts more force than a thin one.

! A pennate muscle of the same thickness as a longitudinal muscle can exert greater force.

" The oblique (slanted) arrangement of fiber allows for a larger number of fibers than in comparable sizes of other classifications.

Muscle Movement ! When tension by the muscle is

sufficient to overcome a resistance and move the body segment.

! The muscle shortens.

! When a muscle slowly lengthens as it gives in to an external force that is greater than the contractile force it is exerting.

! Muscle is acting as a “brake”.

Fig 3.5c

Muscle Movement ! Movers, or Agonists: directly

responsible for producing a movement.

" Prime movers: large impact on movement

" Assistant movers: only help when needed

! This distinction between the various muscles that contribute to a movement is not always clearly defined.

! ers, or Agonists:

Muscle Movement ! Synergists: cooperative muscle function

"Stabilizing, Fixator, & Support Muscles

"Neutralizers – prevent undesired action

Muscle Movement

! Antagonists: have an effect opposite to that of movers (agonist).

! 1st: Antagonists must relax to permit movement.

! 2nd: Acts as a brake at completion of movement.

Movement ! Ballistic Movements: initiated by

vigorous contraction and completed by momentum.

! Throwing, striking, & kicking

! Termination of ballistic action:

1. By contracting antagonist muscles. " Forehand drive in tennis

2. By passive resistance of ligaments or other tissues at limits of motion. " Throwing motion

3. By the interference of an obstacle " Chopping wood

Methods of Studying Muscles ! Conjecture & Reasoning: Using

knowledge of location and attachments, and nature of joints, one can deduce a muscle’s action.

! Dissection: meaningful basis for the visualization of muscle’s potential movements.

! Inspection & Palpation: valuable method for superficial muscles.

! Models: used for demonstration.

! Muscle Stimulation: contraction of individual muscles.

Methods of Studying Muscles ! Electromyography (EMG): based

on the fact that contracting muscles generate electrical impulses.

! Reveals both intensity & duration of muscle activity.

Histology

Connective tissue

Bones

Cartilage

Tendens

Ligaments

Histology Neural Tissue

Motor Neurons

Sensory Neurons

Connector Neurons

Histology

Muscular Tissue

Muscles

The Nervous System

I. Central nervous system (CNS)

A. Brain B. Spinal cord

-The bodies master control unit

The Nervous System

II. Peripheral nervous system (PNS)

A. Cranial nerves (12 pairs)

B. Spinal nerves (31 pairs)

- The bodies link to the outside world

The Nervous System

III. Autonomic nervous system

A. Sympathetic -“fight or flight”

B. Parasympathetic - calming

The Cerebral Cortex

Motor Cortex Sensory Cortex

Motor Neuron

! A single nerve cell consists of a cell body and one or more projections.

" Dendrites: Carry impulses toward cell body.

" Axons: Carry impulses away from cell body.

receives signal

sends signal

The Neuron

Spinal Chord (ventral view)

Spinal Chord (areal view)

Motor Neurons ! Motor neutron axons extend from spinal chord to muscle

! Neuromuscular junctions

Sensory Neurons ! Sensory Neurons:

Situated in a dorsal root ganglion just outside the spinal cord.

! Neuron may terminate in spinal cord or brain.

! A long peripheral fiber comes from a receptor.

Connector Neurons

! Connector Neurons: Exist completely within the CNS.

! Serve as connecting links from sensory to motor neurons.

! May be a single neuron OR

! An intricate system of neurons, whereby a sensory impulse may be relayed to many motor neurons.

Connector Neuron

Connector Neuron

Nerves !Nerves: A bundle of

fibers, enclosed within a connective tissue sheath, for transmission of impulses.

Nerves ! A typical spinal nerve consists of:

" Motor, outgoing (efferent) fibers " Sensory, incoming (afferent) fibers

! Each spinal nerve is attached to spinal cord by an anterior (motor) root and a posterior (sensory) root

Synapse ! Synapse: connection

between neurons.

! Is a proximity of the membrane of an axon to the membrane of a dendrite or cell body.

! The more often a synapse is used the faster a signal will pass through it

! Substance diffuses the synapse and produces an action potential in the postsynaptic neuron (the next neuron).

Muscle Fiber to Motor Neurons ! Muscles contract with various gradations of strength.

"Number of motor units that are activated. "Frequency of stimulation.

Reflex Movement ! A specific pattern of response without volition (will) from the cerebrum.

! Stimulus - receptor organ - sensory neuron - motor neuron - muscle (response)

! Connector neurons often used.

No brain activity involved

Central Nervous System (CNS)

Brain and Spinal Cord

Integrates information it receives and coordinates and influences the activity of all parts of the body of bilaterally symmetric animals

-All multicellular animals except sponges and radially symmetric animals such as jellyfish

Contains the majority of the nervous system.

Central Nervous System (CNS) 1. Cerebral cortex: where consciousness

occurs, initiation of voluntary movement.

2. Basal ganglia: responsible for homeostasis, coordination & some learned acts of posture.

Central Nervous System (CNS)

3. Cerebellum “little brain”: key role in sensory integration, regulates timing & intensity of muscle contraction.

Central Nervous System (CNS)

4. Brain stem: arousal and monitoring of physiological parameters, key facilitory and inhibitory centers.

Central Nervous System (CNS)

5. Spinal cord: contains cell bodies of lower motor neurons, common pathway between CNS & PNS, final point for integration and control.

Central Nervous System (CNS)

What is this Electron Scanning Microscope (ESM) Image of?

Explain the mechanisms at work in this illustration

What’s missing?

Would would be the result of missing this?