Exam 3 Flashcards
(140 cards)
3 basic types of movements
gliding
angular movements
rotation
what is gliding?
where does it occur?
nearly flat surfaces of 2 bones slip across each other
at joints between the carpals and tarsals and between flat articular processes of vertebrae
what are angular movements?
increase or decrease the angle between two bones
flexion, extension, abduction, adduction, circumduction
what is flexion?
give examples
decrease the angle between bones by bringing the bones closer together
- making a fist, bringing head forward, bringing arms forward
what is extension?
give examples?
increases the angle between the joining bones and is a straightening action
- straightening fingers after making a fist, bending head backwards, bringing leg back
what is abduction?
give examples
movement of a limb away from the body midline
- raising arm or thigh laterally, spreading fingers or toes apart
what is adduction?
give examples
movement of a limb towards the body midline
- bringing arm or thigh back towards the body laterally
what is circumduction?
moving a limb or finger so it describes a cone in space
(moving in a circle)
what is rotation?
give examples?
the turning movement of a bone around the longitudinal axis
- turning legs out
_____ is the only movement allowed between the first 2 cervical vertebrae
rotation
4 functional properties of muscle tissue that distinguish it from other tissues
1) contractility - actin and myosin create contractile force in every cell in the body
2) excitability - nerve signals or other stimuli excite muscle cells, causing electrical impulses to travel along the cells’ plasma membrane
3) extensibility - can be stretched, contraction of one skeletal muscle will stretch an opposing muscle
4) elasticity - after being stretched, muscle tissue recoils passively and resumes its resting length
describe skeletal muscle tissue
located in skeletal muscles, discrete organs that attach to and move the skeleton
- striated
- elongated, cylindrical cells
- voluntary movement
describe cardiac muscle tissue
occurs only in the wall of the heart
- striated muscle
- contractions are involuntary
describe smooth muscle
found in the hollow internal organs other than the heart
- lack striations
- cells are elongated
- involuntary movement
cardiac muscle and smooth muscle are collectively called _____ muscle
visceral
what is a sarcomere?
the contractile unit composed of myofilaments made up of contractile proteins
what is a myofilament?
contractile myofilaments have 2 types - thick and thin
- thick filaments contain bundled myosin molecules
- thin contain actin molecules plus the regular proteins troponin and tropomyosin
- the sliding of the thin filaments past the thick filaments produces muscle shortening
what is a myofibril?
rodlike contractile organelles that occupy most of the muscle cell volume
- composed of sarcomeres arranged end to end, they appear banded, and the bands adjacent myofibrils are aligned
what is a muscle fiber (cell)?
an elongated multinucleate cell
- has a banded (stiated) appearance
- surrounded by the endomysium
what is a fascicle?
a discrete bundle of muscle cells, segregated from the rest of the muscle by a connective tissue sheath
- surrounded by a perimysium
what is a muscle organ?
consists of hundreds to thousands of muscle cells, plus connecting tissue wrappings, blood vessels, and nerve fibers
- covered extenerally by the epimysium
what are the 3 connective tissues in and around a skeletal muscle
epimysium
perimysium
endomysium
describe the epimysium
outer layer of dense irregular connective tissue surrounding the whole skeletal muscle
describe the perimysium
within each skeletal muscle, the muscle fibers are separated into groups (fascicle)
surrounding each fascicle is a layer of fibrous connective tissue