Lecture 7 Flashcards
What are the steps to a motor output?
Sensory input
integration
output: effects or causes a response by activating msucles/skeletal system or glands (effectors) via motor output
What are the functions of the bones?
support: bones form the internal framework that support the body and cradle soft organs
protection: bones act as protection for bodys soft organs
movement: works along with muscle to provide locomotion
storage: fat is stored in internal cavities of bones, store house for minerals
production of blood cells: occurs within the marrow of certain bones
How are bones classified?
according to shape/function
- long, short flat, irregular bones
What are the two types of bone tissue?
compact bone: dense, looks smooth and homogeneous
spongy bone: needlelike pieces of bone and lots of open space
What is the general structure of a long bone?
diphysis
epiphysis
What is the diaphysis?
shaft, makes up most of the bone length, compact bone, covered in connective tissue
What is the epiphysis?
ends of the long bone, articular cartilage, covers its external surface
What do joints do?
hold bones together and allow movement
What are the three structural and functional categories of joints?
fibrous joints: contains collagen fibers, no movement
cartilaginous joints: intervertebral joints of the spinal column, articulating bones are connected by pads (discs) slightly moveable
Synovial joints: articulating bone ends are separated by a joint cavity containing synovial fluid = freely moveable
What are some housing systems for dairy cows?
tie stall - stand up, lie down, fixed by neck
free stall - move around freely
What are some housing systems for breeding sows?
gestation stall - 1-2 eek breeding period and pregnancy
farrowing crate - gives birth to piglets 2-3 times a year, sow can lie down and stand up, step forward, step backward
What are some housing systems for laying hens?
non-cage systems - multi-tier system
cage systems
How are muscles connected to bone?
at tendons through collagenic fibers, cross rough bony projections
How do muscles pull the bone?
they contract to the bone which it is attached only in one direction
What is an antagonistic pair of muscles?
one muscle needed to pull bone in one direction, different muscle needed to reverse the reaction
e.g. when the flexor contracts, the ulna moves towards the humerus
What are rules of skeletal muscle activity?
- all skeletal muscles cross as least one joint (with a few exceptions)
- typically, the bulk of a skeletal muscle lies proximal to the joint crossed
- all skeletal muscles have at least two attachments: origin and insertion
- skeletal muscles can only pull: they never push
- during contraction, a skeletal muscle insertion moves toward the origin
Do skeletal muscles generate heat?
body heat is generated as by-product of muscle activity
- skeletal muscle = at least 40% of body mass, most responsible for generating heat
ATP -> 75% into heat production and 25% into muscle contraction
What are some examples of smooth muscle function?
- form valves to regulate the passage of substances through internal body openings
-dilate and constrict pupils - activate arrector pili muscles
What are skeletal muscle fibers?
packaged into skeletal muscles
striated muscle
Do skeletal muscles tire easily?
yes, must rest
What is the structure of a muscle fiber?
sarcomere -> single muscle fiber -> bundle of muscle fibers-> muscle
Where is most of the volume of a muscle fiber?
myofibrils = organelles of bundles of overlapping thick filament and thin filament
What is thick and thin filament?
thick filament - myosin
thin filament - actin
What is a sarcomere?
composed of contractile proteins = actin+myoson
What are the steps of synaptic transmission at the neuromuscular junction?
- AP reaches axon terminal of motor neuron
- ca channels open
- synaptic vesicles release ACh
- ACh diffuses across synaptic cleft and binds to receptors
- simultaneous passage of sodium into muscle fiber and potassium out of the muscle fiber = producing a local change in the electrical conditions (depolarization)
- acetylcholinesterase enzyme breaks down acetylcholine in the
How does a sarcomere contract?
Contracts (shortens_ when its thin filaments slide across its thick filament
- when muscle is fully contracted, the thin filaments overlap in the middle of the sarcomere
How does muscle contraction work?
Myosin head has 2 binding sites - actin and ATP
- hydrolyze ATP for energy to power muscle contraction
myosin head pivots back and forth in an arc changing from high energy to low energy confirguration
- binds with actin, drags actin, release, returns to starting point to repeat same motion with diff actin molecule
What triggers sliding of muscle filaments?
Ca ions, ATP provides energy needed to release and recock each myosin head
What is the monosynaptic stretch reflex?
controls limb movements
- muscle contracts in response to being quickly stretched - single synapse
- helps maintain posture and adjust to maintain body positions
e.g. placing a weight in a persons hand and counterbalancing
What is a polysynaptic reflex?
involve multiple synapses involved in more complex reflexive behaviour
- normally controlled by brain
e.g. golgi tendon reflex
What is muscle fatigue?
inability of the muscle to contract after a prolonged activity, even if it is stimulated, exact mechanism is unknown
lactic acid can build up during anaerobic exercise, it is removed quickly during recovery
What is hypocalcaemia?
milk fever (dogs/cows)
- low blood Ca levels: neuromuscular synapse is blocked
- cows: leads to paresis in ruminants
- dogs: leads to a stiff gait, may be unable to walk, legs become stiff, appears disoriented
