unit 5 Flashcards
functions of the musculoskeletal system
supports and gives shape to the body
protects internal organs
stores calcium
hemopoiesis (blood cell production)
movement
Four major bone types
Long bones - humerus (arm)
Short bones - carpals ( wrist)
Flat bones - frontal (skull)
Irregular bones - vertebrae (spinal cord)
Sesamoid bone - round - patella - kneecap
Diaphysis or shaft
hollow tube of hard compact bone
medullary cavity
hollow area inside diaphysis bone that contains yellow bone marrow
epiphyses or ends of the bone
spongy bone that contains red bone marrow
articular cartilage(Hyaline)
cover epiphyses and functions as cushion
endosteum
membrane lining medulla cavity
periosteum
strong membrane covering bone everywhere except at joint surfaces
structure of flat bones
spongy bone layer sandwiched between two compact bone layers
diploe
spongy bone layer of flat bone
Bone development
early bone development
consist of cartilage and fibrous structures
osteoblast form new bone, and osteoclasts reabsorb bone
osteocytes are inactive osteoblast
cartilage models are gradually replaced by calcified bone matrix
Hyoid bone
in the midline of the neck anteriorly at the base of the mandible and posteriorly at the fourth cervical vertebra
Bones of the right arm
Elbow, and forearm (posterior view)
Bones of the right arm
Elbow, and forearm (Anterior View)
Bones of the right thigh
knee joint and leg
bones of the right foot
phalanges/metatarsals/tarsals
arches of the foot
Normal longitudinal arch
flatfoot
transverse arch
Skeletal vibrations
size - male skeleton generally larger
shape of pelvis - male pelvis deep and narrow
female - pelvis broad and shallow
size of pelvic inlet - female pelvic inlet generally wider, normally large enough for baby’s head to pass through it
pubic angle - angle between pubic bones of female generally wider
Male pelvis is a lot smaller compared to female pelvis
Skeletal Variations
Age differences
the human skeleton reaches its mature state around age 25
after age 50, the density of bone often decreases slowly
environmental factors
without enough calcium or vitamin D, the skeleton may show signs of degeneration
exercise has a profound effect on the skeleton
Hemopoiesis
blood cell production
Articulation of bones
Joints are also called articulations
Joints hold our bones together and make it possible for movement to occur
Every bone except the hyoid (which anchors the tongue) connects to at least one other bone
kinds of joints
diarthroses - free movement
synarthroses - no movement (skull)
amphiarthroses - slight movement (vertebrae)
Diarthroses
Most joints belong to this class
structures freely moveable joints: joints capture and ligaments hold adjoining bones together but permit movement at joint
articular cartilage
cover joints ends of bones and absorbs joints
synovial membrane
lines joints capsule and secretes lubricating fluid
joint cavity
space between joint ends of bones
bursa
fluid filled pouch that absorbs shock
inflammation of bursa called bursitis
Diarthroses
functions of freely moveable joints
ball and socket = shoulder and hip joints
hinge joint - elbow joint =
pivot - dens of axis rotation against atlas/ head of radius rotating against ulna = neck
saddle - carpometacarpal joint of thumb =
gliding - articular processes between vertebrae = intercarpal = intertarsal
condyloid - atlantoocipital joint = jaw = finger
allow different kinds of movements determined by the structure of each joint
Types of joints movements
flexion
reduces angle, as bending the elbow
extension
increases the angle, as in straightening the elbow
abduction
to move a part away from midline
adduction
to add or move a part toward the midline
rotation
spins one bone and relative to another
circumduction
moves the distal end of a bone in a circle, proximal end relatively stable
Synarthroses
no movement
fibrous connective tissue grows between articulation bones
sutures of skull
amphiarthroses
slight movement
cartilage connects articulating bones
symphysis pubis
MUSCLE
Muscular tissue enables the body and its parts to move
Three types of muscle tissue exist in body
movement caused by muscle cells (fibers)
shortening or contracting
Muscle movement occurs when chemical energy (food converted to energy)
Skeletal muscle
Also called striated or voluntary muscle
microscope reveals crosswise stripes or striations
contractions can be voluntarily controlled
Cardiac muscle
Compose of bulk of heart
cardiac muscle fibers are branched
cardiac muscle fiber intercalated disks
cardiac muscle fiber, interconnections allow heart to contract efficiently as a unit
smooth muscle
also called nonstriated or visceral muscle
lacks cross stripes or striation when seen under a microscope; appears smooth
found in walls of hollow structures, such as digestive tract, blood vessel, and so on
contraction not under voluntary control
structure of skeletal muscle
muscle organs: mainly striated muscle fibers and connective tissue
connective tissue forms wrappers around each muscle fiber, around the fascicles of muscle fiber, and one around the entire muscle; fascia surrounds muscle organa and nearby
regions of skeletal muscle
origin; attachment to the bone that remains relatively stationary or fixed when movement at the joint occurs
Insertion: point of attachment to the bone that moves when a muscle contracts
Body: main part of the muscle
muscle attach to the bone by tendons
strong cords or sheets of fibrous connective tissue that extend from them muscle organ
some tendons enclosed in synovial tubes and are lubricated by synovial fluid
bursae
small synovial lined sacs containing small amount of synovial fluid: located between some tendons and underlying bones
structure of skeletal muscle
Structure of muscle fibers (Figure 8-3) and contraction of muscle fibers
Contractile cells are called muscle fibers; connective tissue holds muscle fibers in parallel groupings
Fibers of the cytoskeleton form cylinders that contain thick myofilaments (containing myosin) and thin myofilaments (containing mainly actin)
Basic functional (contractile) unit called sarcomere
Sarcomeres separated from each other by dark bands called Z lines
Sliding filament model explains mechanism of contraction
Thick and thin myofilaments slide past each other to contract
Contraction requires calcium and energy-rich adenosine triphosphate (ATP) molecules
Movement
Muscles produce movement by pulling on bones
as a muscle contracts
The insertion bone is pulled closer to the origin bone
Movement occurs at the joint between the origin
and the insertion
Groups of muscles usually contract to produce a single movement
Prime mover: Mainly responsible for producing a given movement
Synergist muscles: Help the prime mover produce a given movement
Antagonist muscles: Oppose the action of a prime mover in a given movement
Posture
A continuous, low-strength muscle contraction called tonic contraction (muscle tone) enables us to maintain body position
Only a few of a muscle’s fibers shorten at one time
Produce no movement of body parts
Maintain muscle tone called posture
Good posture favors best body functioning
Skeletal muscle tone maintains good posture by counteracting the pull of gravity
Heat production
Survival depends on the body’s ability
to maintain a constant body temperature
Fever: An elevated body temperature; often a sign of illness
Hypothermia: A reduced body temperature
Contraction of muscle fibers produces most
of the heat required to maintain normal body temperature
muscle fatigue
a decrease in maximal force or power production in response to contractile activity
motor unit
stimulation of a muscle by a nerve impulse
is required before a muscle can shorten and produce movement
A motor neuron is the specialized nerve that transmits an impulse to a muscle, causing contraction
Neuromuscular junction (NMJ): Point of contact between a nerve ending and the muscle fiber
Motor unit: Combination of a motor neuron with the muscle fibers it controls (Figure 8-5)
Reduced strength of muscle contraction
Caused by repeated muscle stimulation without adequate periods of rest
Repeated muscular contraction depletes cellular ATP stores and outstrips the ability of the blood supply to replenish oxygen and nutrients
Contraction in the absence of adequate oxygen produces lactic acid, which contributes to muscle soreness
Oxygen debt: Used to describe the metabolic effort required to burn excess lactic acid that may accumulate during prolonged periods of exercise
Labored breathing after strenuous exercise is required to “pay the debt”
This increased metabolism helps restore energy and oxygen reserves to pre-exercise levels
role of the other body system in movement
Muscle functioning depends on the functioning of many other parts of the body
Most muscles cause movements by pulling
on bones across moveable joints
Respiratory, circulatory, nervous, muscular,
and skeletal systems play essential roles
in producing normal movements
Multiple sclerosis, brain hemorrhage, and spinal cord injury are examples of how pathological conditions in other body organ systems can dramatically affect movement
cytokines
fix or repair the damaged muscles
thin Actin
Thick myosin
Sliding filament theory
The muscle contracts when these filaments slide past each other, resulting in a shortening of the sarcomere and thus muscle
muscle contraction is initiated when muscle fibers are stimulated by nerve impulse and calcium ions are released
the troponin units on the actin myofilaments are bound by calcium ions
The point of contact between the nerve ending and the muscle fiber is called
neuromuscular junction
what role does acetylcholine plays in muscle contraction?
excite the activation of muscle function properly
muscle will only contract if an applied stimulus reaches a certain level on intensity
Threshold stimulus: minimal level of stimulation required to cause a muscle fiber to contract
types of skeletal muscle contractions
twitch = is a quick, jerky response to stimulus
tetanic = more sustained and steady
isotonic = produces movement at a joint
isometric = muscle contracts and no movement
concetric contraction
muscle shortens
eccentric contraction
muscle lengthens but still provides work
isotonic contraction =
examples
bicep burls, push-ups, pull-ups, and contractions occurring in the legs while running.
isometric example
planking, isometric exercise is any type of exercise that holds the body in one position
performing heavier task or duty, motor neuron will signals to all our body to help achieve the goal
brain signals to motor neuron, when they receives the message, muscle begins to contract
the bigger the challenges we face, bigger signals will create
injured cells released
cytokines active the immune system to repair the injuries = makes the muscle bigger and stronger
hypertrophy
focuses mostly on developing your muscles
muscle atrophy
the decrease in size and wasting of muscle tissue.
why do we need smooth ER?
production of lipids and some carbs
ribosomes are attached to the rough ER
underneath the golgi, their are granules called lysosomes
why do we need the nucleus?
DNA = master code = codon
ribosomes makes the protein = protein factories = will move around ER
then goes to golgi = packaged and shipped
why do we need smooth eR?
production of lipids
golgi apparatues
packaged the proteins
why do we need mitochondria?
produces energy = power plant
what lysosomes do?
digestive bags
cell membrane
