Lecture Exam 2 Flashcards
review vid 16, 18, 19, 20 Continue from 22
Properties of muscle tissue
Excitability: signals can be sent across tissue
Contractility: When signaled muscles want to contract
Elasticity: muscles can be stretched
Skeletal muscle functions
movement posture temperature storage support
Anatomy of a skeletal muscle fiber
Sarcolemma (transverse tubules attached [special kind of ER (sarcoplasmic Reticulum attached to this (store Ca+ ions)])
Wrapped around myofribrils which are bundles of myofilaments
Two types of myofilaments (for our purposes)
Thin: actin
Thick: myosin
Motor unit
motor neuron + innervated muscle fibers
Muscle contraction
anytime the muscle generates force
isometric: (same length) sum of forces = 0, muscle stays same length
isotonic: (same force) sum of forces =/= 0
- in a concentric contraction: generate more force than load, so muscle shortens
- eccentric: less force than load and muscle lengthens
Muscle patterns
circular
parallel
convergent: wide then narrow
pennate: long central tendom with multiple fibers that come in at an angle
Rules of muscle actions
muscles always pull, never push
if a muscle crosses a joint, it acts on it
A muscle can not act on a joint it does not span / cross
*If asked what a specific muscle does, assume shortening
Somatic Sensory Nervous System
Receives information from skin, fascia, joints, skeletal muscles, and special senses
Sensory = signal in
Visceral Sensory Nervous System
Receives sensory information from viscera
Sensory = signal in
Somatic Motor Nervous System
“Voluntary” nervous system: innervates skeletal muscle
Motor = signal out
Autonomic Motor Nervous System
“Involuntary” nervous system: innervates cardiac muscle, smooth muscle, and glands
Motor = signal out
Nervous tissue comprised…
neurons and glial cells
Unipolar Neuron
Single long dendrite in with axon out, cell body sits to side. These are typically sensory neurons
Bipolar Neuron
Single long dendrite in to cell body and axon out from cell body. Associated with special senses
Multipolar Neuron
Motor Neuron and Inter-neuron
Many dendrites in, one axon out
CNS Glial cells
PNS
Astrocyte
Ependymal cells
Oligodendrocyte
Satellite Cells
Neurolemmocytes
Astrocyte
Part of the blood brain barrier. Neurons do not directly receive nutrients from the blood.
Ependymal Cells
Secrete and produce cerebrospinal fluid. Typically ciliated on outside
Oligodendrocyte
Provides myelin sheath in CNS. Myelinates multiple axons and sections
Satellite Cells
Surround some sensory neuron cell bodies
Neurolemmocytes
Provide myelination for pns neurons. Work one neurolemmocyte at a time unlike the oligodendrocytes multiple coverages
Neurofibril nodes
critical in nerve impulse conduction. Bare spaces along myelinated axon
Saltatory Conduction
the signal jumps from unmyelinated node to node, greatly increasing speed of conduction
