Lecture Exam #3 Flashcards
What are the four major joint categories
Bony/fibrous/catilaginous/synovial
What is a bony joint
An immovable joint, when two bones ossify becoming one
- occurs in either fibrous or cartilaginous joints
What is a fibrous joint
Point at which adjacent bones are bound by collagen fibers that cross the space between them & penetrate into another
What is a cartilaginous joint
2 bones are linked by cartilage
What is a synovial joint
2 bones are separated by joint cavity
What is the general anatomy of joints
Articular cartilage: ends of bones
Joint cavity: holds synovial fluid
Joint capsule: produce synovial fluid in the inner, cellular, synovial mem & forms space for the cavity & has fibrous outer capsule
Articular disc: forms pad between bones, not in all joints
Meniscus: in knee, cartilage does not entirely cross joint
What are the accessory structures associated with synovial joints
Tendon: bind muscle to bone
Ligament: bind bone to bone & merges with periosteum
Bursa: fibrous sac filled with synovial fluid
Tendon sheaths: elongated cylindrical bursa wrapped around a tendon
What is range of motion
Degrees through which a joint can move
What determines range of motion
Structure of the articular surfaces at the end of bones
What are the names for axes rotation
Monoaxial
Biaxial
Multiaxial
Name classes of synovial joints and give example
Ball and socket: humeroscapular (only multiaxial)
Condyloid: metacarpophalangeal (biaxial)
Saddle: trapeziometacarpal (biaxial)
Plane: carpal bones (biaxial)
Hinge: humeroulnar (monoaxial)
Pivot: radioulnar (monoaxial)
Know the pics and motions of the joints.
What are other names for the skeletal muscle cell
Myocytes
What are the characteristics of the skeletal muscle cells
Voluntary and striated
Anatomy of skeletal muscle cells
sarcolemma: outer layer
sarcoplasm: like cytoplasm
myofibrils: individual cylinders
multiple nuclei: purple bumps
sarcoplasmic reticulum (SR): blue veins
terminal cisternae: blue thick horizontal lines
t tubules: purple line in between ^
triad: made of t tubules & terminal cisternae
Differences between myofibers, myofibrils, and myofilaments
Myofilaments make up a myofibril and a bunch of myofibrils make up the myofiber
What is myosin
Makes up thick myofilaments, look like sperm with head poking out
What is actin
In thin myofilaments that connects with myosin during contraction
What are elastic filaments
Titin is a huge springy protein, prevent overstretching
What is a sacromere
Segment from z disc to z disc
What are accessory proteins
Aid in contraction
What accessory protein is involved in muscular dystrophy
Dystrophin
What covers the active site when there is no contraction
Tropomyosin
What holds the tropomyosin in place
Tropinin
What “unlocks” troponin
Calcium
What is a motor unit
One neuron innervates several muscle fibers
What are differences between large and small motor units
Small: fine degree of control (3-6 fibers per neuron) ex: hands
Large: more strength than control (many muscle fibers per neuron) ex: back
What is the neuromuscular junction
Point where a nerve fiber meets muscle fiber
What is the chemical neurotransmitter used in NMJ
Acetylcholine
What are action potentials
Quick up and down voltage shift from negative RMP (resting mem potential) to positive to negative again
What goes on during each stage of electrically excitable cells
- Ion gates open in plasma mem.
- Na+ instantly diffuses down concentration gradient
- ^^ causes depolarization (inside of the mem. Becomes briefly positive)
- Immediately Na+ gates close and K+ gates open
- K+ leaves the cell due to sodium positive charge
- ^^ causes repolarization (loss of positive K+ ions turns mem. Negative again)
- Action potential causes another one to happen immediately in front of it
What are the four phases involved in muscle contraction
Excitation
Excitation and contraction coupling
Contraction
Relaxation
What goes on during excitation
- Nerve signals open voltage gated calcium channels in synaptic knob
- Calcium stimulates exocytosis of ACh from synaptic vesicles
- ACh released into synaptic cleft
- 2 ACh molecules bind to each receptor protein, opening Na and K channels
- Na enters shifting to positive, then K leaves which puts it back to negative
What are contractile and regulatory proteins
Contractile: myosin and actin
Regulatory: tropomyosin and troponin
What occurs in rigor mortis
Hardening of muscles and stiffening of body beginning 3-4 hours after death
- Ca activates myosin actin cross bridge but there is not ATP to cause relaxation
What goes on during excitation-contraction coupling
- Action potential spreads into T tubules
- Causes opening voltage gated ion channels in tubules & Ca channels in SR
- Ca enters the cytosol & binds to troponin
- Troponin-tropomyosin changes shape & exposes active sites
What goes on during contraction
- Myosin ATP hydrolyzes to ADP + Pi which activates the cocking of myosin head
- Head binds to active site forming a myosin actin cross bridge
- Myosin head release ADP + Pi, pulling thin filament past thick (power strokes)
- Binds more ATP myosin releases actin and process is repeated
What goes on during relaxation
- Nerve stimulation & ACh release stops
- AChE breaks down ACh & fragments reabsorbed into the synaptic knob
- Ca pumped back into SR by active transport
- Tropomyosin reblocks active sites
What are immediate energy needs
Short intense exercise
Oxygen supplied by myoglobin first then quickly depleted, ATP derived from phosphate transfers (phosphagen system)
What are short term energy needs
Anaerobic fermentation: enables cells to produce ATP in absence of oxygen, yields little ATP and toxic lactic acid, major in muscle fatigue
-Converts glucose to lactic acid
-Produces enough ATP for 30-40 seconds of maximum activity
What are long term energy needs
After 40 sec or so of exercise, respiratory & cardiovascular systems “catch up”
- aerobic respiration (requires continual supply of oxygen) produces 36 ATP per glucose, efficient means of meeting the ATP demands of prolonged exercise
What are the differences between type 1 and type 2 fibers
Type 1: slow oxidative, slow twitch, red
- abundant mitochondria, myoglobin and capillaries, adapted for aerobic respiration and fatigue resistance
Type 2: fast glycolytic, fast twitch, white
- fibers well adapted for quick responses not for fatigue resistance, poor in mitochondria, myoglobin, and blood capillaries
What are the histological characteristics & properties of cardiac cells
Striated, myocytes are shorter & thicker, one nucleus, involuntary, intercalated discs, mainly use aerobic respiration, auto rhythmic , contract in unison, highly resistant to fatigue
What are the histological characteristics & properties of smooth muscle cells
Composed of myocytes that have fusiform shape, involuntary, one nucleus, no nervous stimulation, no striations, no sarcomeres, intermediate filaments
What are the two types of smooth muscle cells
Multiunit: autonomic innervation similar to skeletal muscle, in arteries and pulmonary air ways, each unit contracts independently
Single unit: wide spread, most blood vessels, contain gap junctions, contract as one
How does stimulation, contraction, and relaxation work in smooth muscle (calmodulin)
Stimulation: can contract without nervous stimulation, contract in response to chemical stimuli
Contraction: begins in response to Ca, binds to calmodulin on thick filaments
Relaxation: this and ^^ are slow compared to skeletal, latch bridge mechanism is resistant to fatigue
What are other unique features of smooth muscle cells
Ability to contract against a stretched organ and peristalsis
What are the two main parts of the nervous system
Central nervous system (CNS)
Peripheral nervous system (PNS)
What are the 3 steps of nervous system
- Sense organs receive information
- Brain and spinal cord processes this information
- Brain and spinal cord issue commands to muscles and gland cells
What is CNS
Brain and spinal cord enclosed in bony coverings, enclosed by cranium & vertebral columns
What is PNS
All nervous system except brain and spinal cord, composed of nerves and ganglia
What are the divisions for PNS and what do they do
Sensory division: Carries signals from….
- somatic: from skin, muscles, bones, joints
- visceral: from viscera of thoracic & abdominal cavities, heart, lungs, stomach, urinary bladder
Motor division: carries signals from CNS to…
- somatic: skeletal muscles
- visceral: glands, cardiac/smooth muscle
Sympathetic: arouse
Parasympathetic: calming
What are the three universal properties of neurons
Excitability, conductivity, secretion
What are the three functional classes of neurons
Sensory (afferent): specialized to detect stimuli
Interneurons (association): receive signals from many neurons & carry out integrative fxn
Motor (efferent): send signals out to muscles & gland cells
