anatomy exam 2

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anterior and posterior cruciate ligaments

"cross"

fused tetanus

(100% wave summation) is the most forceful contraction that can be produced by a muscle

voltage gated k+ channels gate open at

+30mV

voltage-gated na+ channels gate open at

-65mV

number of designation of thumb metacarpal

1

triad made up of

1 t-tubule flanked by 2 terminal cisterns of the sarcoplasmic reticulum

crossbridge cycling steps

1)crossbridge formation •myosin head attaches to exposed binding site on actin 2)power stroke •myosin head pulls thin filament toward center of sarcomere 3) release of myosin head 4) reset myosin head

excitation-contraction coupling

1. action potentials trigger release of ca2+ from the sarcoplasmic reticulum 2. troponin binds ca2+ which triggers crossbridge formation between thin and thick filaments 3. crossbridge cycling leads to sarcomere shortening and muscle cell contraction 4. as the muscle cell shortens, there is a change in sarcomere banding pattern 5. muscle cell relaxation reflects elimination of neurotransmitter at the synapse and clearing of ca2+ from the sarcoplasm

number of false ribs

10

number of thoracic vertebrae

12

number of tarsal bones

14

number of vertebrosternal ribs

14

number of carpal bones

16

number of phalanges in each great toe

2

number of phalanges in one thumb

2

number of phalanges is right thumb

2

number of ribs

24

number of cuneiform bones in each foot

3

number of phalanges in little toe

3

number of phalanges in right index finger

3

number of floating ribs

4

number of rudimentary vertebrae forming the tailbone

4

number of bones forming the instep of each foot

5

number of designation for small toe metatarsal

5

number of lumbar vertebrae

5

number of metacarpal bones in right hang

5

number of metatarsal bones in right foot

5

number of rudimentary vertebrae forming the sacrum

6

number of vertebrochondral ribs

6

number of bones forming tarsus

7

number of cervical vertebrae

7

ligament examples

ACL, UCL

acid base and electrolyte balance

Ca++ released from bone

thyroid hormone

Essential to bone growth; enhances synthesis and effects of growth hormone, but excesses can cause hypercalcemia, increased Ca2+ excretion in urine, and osteoporosis

blood cell formation

RBC and WBC form in the red bone marrow

displaced fracture

The portions of bone are out of anatomical alignment

fascicle

a bundle of muscle fibers within a muscle. supplied by nerves and blood vessels and enclosed in a fibrous perimysium that separates it from neighboring fascicles.

myofibril

a bundle of protein myofilaments within a muscle fiber; myofibrils collectively fill most of the cytoplasm. each surrounded by sarcoplasmic reticulum and mitochondria. has a banded (striated) appearance due to orderly overlap of protein myofilaments.

evidence of sarcomere shortening is observed as

a change in striation pattern

unequal distribution of na+ and k+ by this protein leads to

a charge difference across the plasma membrane

muscle

a contractile organ, usually attached to bones by way of tendons. composed of bundles (fascicles) of tightly packed, long, parallel cells (muscle fibers). supplied with nerves and blood vessels and enclosed in a fibrous epimysium that separates it from neighboring muscles.

tropomyosin

a fibrous, string-like protein associates with the thin filament along its length

despite being hardened tissue, the skeletal system is

a flexible framework for the body

troponin

a globular protein attaches to tropomyosin and will re-position tropomyosin along the thin filament in the presence of ca2+

shaft of long bone surrounds

a medullary cavity - site of yellow marrow in adults, red marrow in young children

motor unit

a motor neuron and all the muscle fibers it controls

nerve connections are severed or poisoned

a muscle is paralyzed

at the same time the bone collar is forming

a primary ossification center develops

sarcomere

a segment of myofibril from one z disc to the next in the fiber's striation pattern. hundreds of sarcomeres end to end compose a myofibril. the functional, contractile unit of the muscle fiber.

muscle fiber

a single muscle cell. slender, elongated, threadlike, enclosed in a specialized plasma membrane (sarcolemma). contains densely packed bundles (myofibrils) of contractile protein filaments, multiple nuclei immediately beneath the sarcolemma, and an extensive network of specialized smooth endoplasmic reticulum (sarcoplasmic reticulum). enclosed in a thin fibrous sleeve called endomysium.

polarization

a state of charge separation across the membrane

resting membrane potential (rmp) is seen in

a waiting excitable cell

the false pelvis is bounded anteriorly by the

abdominal wall

rigor mortis peaks

about 12 hours after death, then diminishes over the next 48 to 60 hours

fossa on coxal bone that articulates w/ femur

acetabulum

fossa on coxal bone that articulates with the femur

acetabulum

in adult skeleton, the embryonic coxal bones meet in the

acetabulum

chemically gated channels are concentrated in the junctional folds at the nmj and will bind

acetylcholine (ach) released by the motor neuron

process on scapula that articulates with clavicle

acromion

process on scapula that articulates with the clavicle

acromion

the scapular spine terminates as the

acromion process

thin filaments

actin, troponin, tropomyosin

opening of voltage-gated ion channels trigger

action potential across the entire cell surface and along the t-tubules

fat pads

adipose tissue between synovial membrane and fibrous capsule, move with joint

junctional folds function

allows for amplified packing of receptor proteins for the neurotransmitter in the muscle cell membrane, means the muscle cell has a great capacity to capture the neurotransmitter when it is released by the neuron, makes for more efficient activation of the muscle cell

small motor units have less than five muscle fibers

allows for precise control of force output (e.g. eye muscles, muscles that control the fingers)

large motor units have thousands of muscle fibers

allows for production of large amount of force (but not precise control, e.g. postural muscles, muscles of lower limbs; gastrocnemius muscle of the calf has 1,000 muscle fibers per neuron)

rapid diffusion of na+ and k+ ions across the membrane through regulated ion channels

allows the muscle cell to activate and trigger internal events that lead to contraction

sternocleidomastoid action

alone: laterally rotates neck to opposite side together: flexes neck

spongy bone develops

along lines of stress to reinforce bone structure

voltage gated ion channels are located

along the entire length of the sarcolemma and the t-tubules and are critical to trigger contraction of the muscle cell

triads are located

along the length of the myofibril; as calcium rains out of the sr....it covers the underlying sarcomeres

isometric muscle contraction

although muscle is producing tension, it is insufficient to overcome resistance (its load), muscle is crossbridge cycling but its length stays the same (e.g., holding a weight while arm doesn't move), important in postural muscle function and antagonistic muscle joint stabilization

sockets of jaw in which teeth lie

alveoli

sockets on the superior margin of the mandible in which teeth lie

alveoli

muscle fibers exhibit a resting membrane potential (rmp)

an electrical charge across the plasma membrane when the cell is at rest; it is also referred to as the resting membrane voltage (charge is measured in volts), this charge makes the muscle cell excitable! electrically charged cells are excitable -they are responsive to and capable of conducting electricity

calcitonin

antagonist of parathyroid hormone

anterior termination of iliac crest

anterior superior spine

bone also grows in width through a process called

appositional growth

bone remodel and thicken along

areas where there is the most stress to provide support

superficial fascia

areolar and adipose tissue, located superficial to deep fascia, separates muscles from skin

cartilage covering epiphyseal surfaces of long bones

articular (hyaline)

heat production by skeletal muscles

as much as 85% of our body heat

growth factors

at least 12 hormone like substances produces in bone itself that stimulate neighboring bone cells, promote collagen

acetylcholine (ach) diffuses across the synaptic cleft and arrives

at the muscle cell membrane where it binds to the ach receptor

the first cervical vertebra is called the

atlas

myosin head has this enzyme action

atp adp + pi

myasthenia gravis

autoimmune disease in which antibodies attack neuromuscular junctions and bind ach receptors together in clusters

cartilage blood supply

avascular - nutrients obtained via diffusion from surrounding tissues

division of the skeleton that lies around the body's center of gravity

axial

pivot

axial

lateral border of the scapula.

axillary

the lateral border of the scapula is the

axillary border

shaft of long bone forms the

axis

the second cervical vertebra is called the

axis

neuron features

axon terminal (synaptic knob) with secretory vesicles containing the neurotransmitter acetylcholine, secretion of acetylcholine into the synaptic cleft is triggered by the arrival of an electrical current, synaptic cleft separates membrane of neuron and muscle cell: enzyme acetylcholinesterase is located within this gap; will degrade acetylcholine

radial collateral ligament

bans of strong flexible tissue attaches the humerus to the ulna

h zone

bare zone of no-overlap in the middle region of the thick filament, m line

the sarcomere

basic functional unit of the myofibril, consists of overlapping array of thin and thick filaments (myofilaments)

ca2+ diffuses out of cisterns and into the sarcoplasm

bathing the underlying sarcomeres within the myofibrils

the muscle cell is back at rest electrically

before it even begins force production - action potential has formed and the cell has returned to resting voltage before cross bridge formation begins

where you activate a nerve cell

begins a pathway of electrical current delivery through the cns and out the pns to the muscle

collagen fibers allow for

bend but not break of bones

condylar

biaxial

movement in two planes of space

biaxial

saddle

biaxial

groove separating tubercles of humerus

bicipital or intertubercular

each head can

bind and hydrolyze (breakdown) atp; so myosin is the protein that uses energy to fuel muscle action

compact bone fibers in ecm

bind inorganic minerals (calcium, phosphorus)

stimulation at the nmj through

binding of acetylcholine to its receptor in the muscle cell membrane

z line

bisects the i band; consists of proteins to which the thin filaments attach; one sarcomere is the area between successive z-lines

the perichondrium is invaded by

blood vessels to bring chondrogenic cells

horizontal portion of mandible forming the chin

body

portion of mandible that forms chin

body

the middle part of the breast bone is the

body (gladiolus)

avulsion fracture

body part is completely severed

bone remodeling is a balance of

bone deposition and bone resorption

osteogenic layer of periosteum

bone forming cells (osteogeneic), gives rise to osteoblasts

complete fracture

bone is broken into two or more pieces

parathyroid hormone controls

bone remodeling by maintaining homeostatic levels of Ca++ in the blood

rotation

bone turns along axis

movement

bones act as levers for muscles

comminuted fracture

bones break into multiple pieces, common fracture in elderly (brittle bones)

cartilaginous joints

bones held together by cartilage

fibrous joints

bones held together by fibrous CT

synovial joints

bones held together via a synovial cavity/membrane

mineral storage

bones store Ca++ and PO4-3

protection

bones surround organs

the bony ring formed by the sacrum, coxae, and coccyx

bony pelvis

each nerve fiber (axon)

branches out to form an association with a number of muscle fibers (cells) within the same muscle

within the cleft is the enzyme acetylcholinesterase (ache)

breaks down ach, allowing for relaxation (it clears the neurotransmitter from the synaptic cleft)....this is critical to permit muscle cell relaxation after a contraction event has occurred

twitch

brief contraction produced in response to a single stimulus

osteogenesis imperfecta

brittle bone - defect in collagen protein leading to a lack of tensile strength, collagen cant be the glue anymore so bones break under stress

triangular (convergent) muscles

broad at one end and narrow at the other

medial (tibial) collateral ligament

broad, flat ligament that prevents medial displacement

depressed fracture

broken portion of bone forms a concavity, as in skull fractures

multipennate

bunches of feathers converge to single point

thick filaments

bundles of many myosin protein molecules (look like golf clubs)

myofibrils consist of

bundles of myofilaments (contractile proteins)

deep fascia

bundles various muscles together within compartments to form working groups, external to epimysium, separates muscles while binding them, contains nerves, blood vessels

action potentials triggered

by binding of acetylcholine (ach) to its receptor

medial and lateral menisci

c shaped fibrocartilage rings that attach in the intercondylar area of tibia, attached via the transverse ligament of knee, lateral meniscus more mobile, stabilize knee during movements; cushion joint and allow proper movement between articular surfaces

troponin

ca2+ binding protein

heel bone

calcaneus

terminal cisterns serve as reservoirs for

calcium ions

inorganic components of bone (hydroxyapatites)

calcium phosphate, calcium carbonate

condyle on humerus that articulates with radius

capitulum

condyle on humerus that articulates with the radius

capitulum

endocondral ossification continues as

cartilage grows during development

zone of calcified cartilage

cartilage matrix becomes calcified

plates of hardened matrix wrap around

central canal (haversian)

cns

central nervous system (brain and spinal cord)

branched spinous process are characteristic of

cervical v

transverse foramina are characteristic of

cervical vertebrae

ion channels are specific

channels that permit na+ to diffuse do not permit k+ to diffuse and vice versa; this means that distinct ions can be moving across the membrane at different times

ion channels

charged ions may diffuse across the muscle cell membrane if a channel created by an integral membrane protein is/are present and is open

zone of proliferation

chondrocytes undergoing mitosis in response to factors like IGF-1

cartilage cell types

chondrogenetic, chondroblasts, chondrocytes

bone joining pectoral girdle to axial skeleton

clavicle

voltage-gated ion channels

closed at one membrane voltage but will trigger (gate) open at another

bursa/tendon sheaths

closed regions of synovial membrane, no real space between layers - only thin layer of serous fluid, reduce friction as structures move over each other, occur between skin and bone beneath deep fascia, over tendons, etc

chemically-gated ion channels

closed until the cell is exposed to a specific chemical compound example below depicts a channel protein that functions as a receptor for a neurotransmitter; when the neuron releases the chemical at the synapse the receptor binds it and opens as a gated ion channel

orbicularis oculi action

closes eye; produces blinking and squinting

skeletal muscle control

cns motor neuron activates muscle (we'll cover this later in the nervous system)...but this is where you determine the movement

the distal bone of the vertebral column

coccyx

the tailbone of the cervical vertebral column is called the

coccyx

sharpey's fibers

collagen fibers that extend from the outer layer of periosteum into the bony matrix

zone of reabsorption

collagen matrix is broken down and new bone is produced

organic componenents of bone

collagen, glycosaminoglycans, proteoglycans

two major types of bones

compact and spongy

flat, irregular, and short bones are composed of

compact bone layers surrounding spongy bone, hyaline cartilage lining areas of articulations

long bones are composed of

compact bone surrounding marrow filled cavity, spongy bone in both ends (red marrow for hematopoises), hyaline cartilage lining areas of articulations

bone tissue types

compact bone, cancellous (spongy) bone

transverse abdominis action

compression of abdomen

rectus abdominis action

compression of abdomen, flexion and rotation of trunk/vertebral column

external oblique action

compression of abdomen: alone: rotation of trunk/vertebral column together: flexion of trunk/vertebral column

internal oblique action

compression of abdomen; alone: rotation of trunk/vertebral column together: flexion of trunk/vertebral column

rounded convex projection that articulates with another bone

condyle

articulations of knee joint

condyles of the femur to condyles of tibia, between the patella and femur

endosteum composition

connective tissue layer with osteogeneic cells

perforating (volkman's) canals

connects medullary cavity to central canal, connect nerves and blood supply from periosteum to central canal

m line

contains proteins that help anchor thick filaments in place

effective contraction of the entire muscle typically requires

contraction of several motor units at once

process on scapula anterior to glenoid fossa

coracoid

lateral (fibular) collateral ligament

cord like ligament that prevents lateral displacement

suture between frontal and parietal bones

coronal

depression on anterior surface at distal end of humerus

coronoid fossa

the anterior proximal process of the ulna is the

coronoid process

cavity encasing the brain

cranial

encases brain

cranium

narrow ridge of bone serving as a site for muscle attachment

crest

superior border of the ilium

crest

perforated bony plates lateral to the crista galli

cribiform plates

upward projecting process of ethmoid bone

crista galli

as long as atp is present and ca2+ is available in the sarcoplasm

crossbridge cycling will continue......and is absolutely necessary to produce full contraction of the cell and the whole muscle

binding between myosin and actin

crossbridge: cycling of crossbridges and filament sliding leads to contraction of the muscle cell

short bone

cube shape

osteoblasts

cuboid shaped cells that produce the matrix, non mitotic, most die once matrix is formed

articular cartilage function

cushioning and stress absorbing

a band

dark, anisotropic region, contains thick filaments and overlapping thin filaments, h zone, makes up central region of sarcomere

flexion

decreases the angle of a joint

osteoclasts function

degrade old bone

osteoclasts invade the area and

degrade the mixed matrix

functional classification of joints based upon

degree of movement allowed

endomysium

delicate connective tissue covering individual muscle cell

the axon of nerve cell

delivers an electrical current to a spinal motor neuron sitting in the spinal cord

the vertical protrusion of the axis is the

dens (odontoid process)

perimysium

dense connective tissue wrapping multiple cells/fibers together into fascicles, carries blood vessels, nerves, and stretch receptors that detect degree of extension of the muscle

epimysium

dense connective tissue wrapping multiple fascicles together to form complete muscle

outer layer of periosteum composition

dense irregular connective tissue

tendon

dense regular connective tissue that connect muscle to bone

growth plate fractures usually heal normally

depend on severity and age, splinting vs surgery

platysma action

depresses lower lip, tenses skin of neck

internal intercostals action

depresses ribs during expiration

curare

derived from a plant and used as a poison by south american native peoples to hunt prey in trees using blowgun darts, binds to ach receptors and blocks ach from binding; induces flaccid paralysis

osteoclasts

derived from bone marrow cells, degrade bony matrix

osteocytes

derived from osteoblasts and maintain tissue environment, many projections that allow communication with other bone cells f

shaft of long bone

diaphysis

major difference in secondary ossification center

diaphysis is hollowed out to form the medullary cavity surrounded by compact bone with spicules, epiphyses are surrounded by compact bone with a spongy center

synovial joint movement

diarthrotic

osteoprogenitor cells

differentiate into osteoblasts which being to lay down bony matrix on cartilage - mixed cartilage/bone matrix now exists

this prevents nutrients from

diffusing and the chondrocytes dying

cartilage obtains nutrients via

diffusion (limited thickness)

terminal cisterns

dilated end-sacs of sr which cross the muscle fiber from one side to the other

hematopoiesis sites

diploe of flat bones in skull, os coxa, etc

muscle fibers of one motor unit are

dispersed throughout muscle...they are not all clustered in a bunch

summary of the nerve-muscle cell relationship

each muscle cell interacts with only one neuron but each neuron interacts with more than one muscle cell

organization of skeletal muscle permits

easy interaction between thin and thick filaments which is necessary for contraction

somatic motor neurons carry

electrical impulses from the spinal cord to multiple muscle cells within the target muscle

masseter action

elevates and protracts mandible

temporalis action

elevates and retracts mandible

epicranius action

elevates eyebrows and wrinkles forehead

external intercostals action

elevates ribs during inspiration

delicate membrane lining the medullary cavity of a long bone

endosteum

inner layer of bone

endosteum

the chondrocytes here

enlarge, vacuolize, and secrete molecules that calcify the matrix (not the same as bone hardening)

ach receptor is a chemically-gated ion channel

entry of na+ ions leads membrane to depolarization at the nmj

raised area on a condyle

epicondyle

muscles of facial expression

epicranius, orbicularis oculi, orbicularis oris, buccinator, zygomaticus, platysma

muscle coverings

epimysium, perimysium, endomysium, deep fascia

region for longitudinal growth in developing long bone

epiphyseal disk

growth plates span

epiphyseal plates of cartilage

ends of bones are called

epiphysis - usually broader for muscle attachment

epiphyseal fracture

epiphysis separates from the diaphysis along the epiphyseal plate

major regulator in bone remodeling

estrogen

bone forming inferior border of anterior portion of the cranium

ethmoid

compact bone replaces

every ~10 years

canal leading to the eardrum and middle ear

external auditory meatus

cartilage in the skeletal system

external ear, intervertebral discs, pubic symphysis, joints (articular cartilage)

muscles of respiration

external intercostals, internal intercostals, diaphragm

midline prominence posterior to the foramen magnum

external occipital protuberance

wormian bone

extra bones usually located between cranial bone (sutural)

parathyroid feedback loop

falling of calcium levels stimulates the release of PTH, parathyroid gland release PTH, osteoclasts degrade bone matrix and release Ca++ into blood, PTH stimulates osteoclasts and inhibits osteoblasts

(t/f) the clavicle articulates with the gladiolus if the sternum

false

(t/f) the head of the radius articulates with the trochela of the humerus

false

(t/f) the scapula articulates with the vertebral column

false

(t/f) the semilunar notch of the ulna articulates with the capitulum of the humerus

false

muscle structure reflects organization of fascicles

fascicle orientation determines how the muscle will do its work

bipennate

fascicles approach tendon from both sides

unipennate

fascicles approach tendon from one side

synovial joint accessory structures

fat pads, bursa/tendon sheaths

pennate muscles

feather shaped - unipennate, bipennate, multipennate, circular muscles

pelvis with larger and more circular inlet

female

the bones of the pelvis are more delicate in

female

largest and heaviest bone of the body

femur

spaces between adjacent vertebral bodies are filled with

fibrocartilage

symphysis

fibrocartilage, slight movement - compression, intervertebral discs, pubic symphysis

solid joints

fibrous and cartilaginous

ligaments

fibrous connective tissue connecting bones together

intramembranous ossification

fibrous membrane replaced by bone tissue, bones of skull and clavicles

tropomyosin

fibrous protein

myofilaments

fibrous protein strands that carry out the contraction process. two types: thick filaments composed mainly of myosin, and thin filaments composed mainly of actin. thick and thin filaments slide over each other to shorten each sarcomere. shortening of end-to-end sarcomeres shortens the entire muscle.

types of structural joints

fibrous, cartilaginous, synovial

lateral bone of the lower leg

fibula

non-weight bearing bone of lower leg

fibula

myofibrils

fill the sarcoplasmic space; contain high density of myofilaments - thick and thin filaments

elastic cartilage

fine collagen fibers with lots of elastic fibers

hairline fracture

fine crack in which sections of bone remain aligned, common in skull

narrow slit-like opening that serves as a nerve passageway

fissure

people whose longitudinal arches have fallen suffer from

flat feet

elbow joint allows for uniaxial movement

flexion and extension

circumduction

flexion, abduction, extension, and adduction, distal end moves, proximal end stationary

unossified membranous area of fetal skull

fontanel

opening though a bone

foramen

large opening in the base of the occipital bone

foramen magnum

opening of occipital surrounding brain stem

foramen magnum

circular muscles (sphincters)

form rings around body openings

multiple cell types are important in _____ and ____ of bone tissue

formation, maintenance

depression along surface where nerve terminal is positioned

forms a sort of basin-like depression that helps capture neurotransmitter when released at the synapse, makes for more efficient activation of the muscle cell

shallow depression that frequently forms a socket for another bone in a joint

fossa

colles fracture

fracture of the distal radius and ulna at the wrist, common in osteoporosis

pott fracture

fracture of the lower end of the fibula, tibia, or both, common sports injury

spiral fracture

fracture spirals around axis of long bone; results from twisting stress, common of abuse - adult grabbing child by the arm

diarthrotic joint

free movement allowed

bone forming anterior superior portion of skull

frontal

bone forming forehead and superior parts of orbits

frontal

bone forming superior anterior portion of the skull

frontal

chemically-gated ion channels

gate open when a chemical is applied to the membrane that is received/bound by a receptor that gates open as an ion channel

voltage-gated ion channels

gate open with a change in charge across the membrane

action potentials triggered at the motor end plate by

gating of the ach receptor channel trigger action potentials in the membrane regions surrounding the nmj by opening of voltage-gated ion channels

when voltage reaches + 30 mv

gating potential for voltage-gated k+ channels; these pop open allowing k+ to rush out of the cell, na+ channels also inactivate therefore na+ ion movement across the membrane stops.

cartilage matrix

gel like composition

fiber at resting length

generates maximum contractile force, optimal overlap of thick and thin filaments

fiber at a shortened length

generates weaker force, filament movement is limited (already close to z disc)

fiber at an extended length

generates weaker force, minimal thick and thin filament overlap for crossbridge formation

smooth area of frontal bone between the eyes

glabella

depression on scapula that articulates with the humerus

glenoid fossa

deep notch just below the posterior inferior spine of the ilium

greater sciatic notch

large process lateral to neck of femur

greater trochanter

large process lateral to the neck of the femus

greater trochanter

rounded lateral process distal to anatomical neck of humerus

greater tubercle

part of sphenoid seen on side of skull

greater wing

advantage of using membranes and cartilage as models

growth and flexibility, tissues form framework accommodate mitosis

major drivers of bone growth in children

growth hormone and thyroid hormone

bone matrix

hardened calcified matrix

mineralization of bone

hardening

rigor mortis

hardening of muscles and stiffening of body beginning 3 to 4 hours after death -deteriorating sarcoplasmic reticulum releases ca^2+, deteriorating sarcolemma allows ca^(2+) to enter cytosol, ca^(2+) activates myosin-actin cross-bridging, muscle contracts, but cannot relax

each head

has a binding site where it can attach to a thin filament

myosin head is in the "cocked" high-energy position

has adp + pi bound to the head, previously bound atp and broke a phosphate bond, energy from the bond allowed the protein to extend at the hinge, in this conformation the binding sites for actin are exposed

sarcolemma (plasma membrane)

has t-tubules (transverse tubules) that extend deep into the cell: these are literally a deep internal extension of the cell surface; they open at the surface as a "pore"; the interior fluid in the tube is actually the extracellular fluid

sarcoplasm (cytoplasm)

has typical organelles including many mitochondria for energy production plus contractile proteins

extension carried on a narrow neck that takes part in the formation of a joint

head

proximal disc-shaped end of radius

head

proximal expanded portion of fibula.

head

proximal expanded portion of the fibula

head

myosin head is in the "cocked" position

head previously bound atp and broke a phosphate bond, adp and pi are currently bound to the head (energy was used to extend the head at the hinge)

actin

helix of 2 fibrous strands of actin

spongy bone is the main site of

hematopoiesis in adults

cartilage ability to withstand tension/compression comes from

high water percentage

bone blood supply

highly vascularized, direct nutrient delivery to tissue

the knee joint

hinge joint allowing flexion and extension of the leg

spongy bone composition

holes/spaces filled with marrow

____ play a significant role in regulating bone growth

hormones

bone growth and remodeling occur under the control os

hormones (feedback loop) and physical/mechanical stressors

zone of reserve cartilage

hyaline cartilage

endochondral ossification uses ____ template for bone development

hyaline cartilage - bone formation chases cartilage growth

endochondral ossification

hyaline cartilage replaced by bone tissue in all bones below base of skull (besides clavicles)

synchodrosis

hyaline cartilage, no movement at rib 1 sternal junction, slight movement at ribs 2-7 sternal junction - synovial joints

cartilage tissue types

hyaline, elastic, fibrocartilage

anteriorly located between mandible and larynx

hyoid

bone located in the throat above the larynx that does no articulate with any other bone

hyoid

weakest layer of cartilage

hypertrophic zone

superior ridge of os coxa

iliac crest

connective tissue coverings located more superficially

important to groups muscles together within regions or into working groups (such as the quadriceps or hamstrings)

wave of excitation

impulse; the impulse is being transmitted along the complete length of the very large muscle cell starting from a pinpoint area, the nmj

the stimulus induces a change in membrane voltage

in the direction of depolarization (toward a less negative value)

greenstick fracture

incomplete break (one side breaks, other bends), common fracture in kids (bones more flexible)

torus (buckle) fracture

incomplete fractures of the shaft of a long bone, most common in children (growing bones), fall on outstretched arm or leg - load absorbed in distal portion of bone

loss of estrogen

increased bone resorption

PTH also

increases phosphate excretion, enhances calcium absorption (and therefore decreases excretion)

hyperextension

increases the angle

curved bones protruding from the lateral walls of the nasal cavities

inferior conchae (turbinates)

curved bone attached to wall of nasal fossa

inferior nasal concha

opening under each o

infraorbital foramen

depolarized state

inside is less negative than it was at the start (now in fact is positive if large amount of na+ entered the cell)

hyperpolarized state

inside is more negative than it was at the start (lost more + charged ions in the intracellular space....)

polarized state

inside is negative relative to outside

sarcoplasmic reticulum (sr)

internal membrane complex similar to smooth endoplasmic reticulum

posterior ridge connecting trochanters of femur

intertrochanteric crest

ridge on the posterior surface of the femur connecting the two trochanters

intertrochanteric crest

the opening in the vertebral column for spinal nerves are the

intervertebral foramina

motor neuron activates and releases neurotransmitter

into the synaptic cleft

sarcolemma and t-tubules

inward projecting narrow tubular extensions of the cell membrane; high density of voltage-gated ion channels along all membrane surfaces

at the beginning of contraction

isometric phase, muscle tension rises but muscle does not shorten

muscle begins to shorten and move the load

isotonic phase

myosin head will release from actin when

it binds a fresh molecule of atp

troponin changes shape when

it binds ca2+; the shape change causes it tug on tropomyosin

when ach binds to the receptor

it gates open as a chemically-gated ion channel

when the neurotransmitter is released by the nerve cell

it has to diffuse a short distance to reach the muscle cell membrane

when voltage reaches - 65 mv

it is the gating voltage for voltage-gated na+ channels in the membrane; these channels pop open quickly and that allows na+ to rush into the cell

in the case of the ach receptor at the nmj

it permits the passage of na+ across the membrane, na+ will diffuse into the muscle cell down the concentration gradient, this will lead to depolarization of the membrane at the motor end plate (the area at the nmj)

since muscles have multiple motor units

it provides an ability to sustain long-term contraction as motor units will take turns contracting (critical for postural muscles)

bones bearing a groove that serves as a passageway for tears

lacrimal

bones forming sides of the cranium

lambdoidal

suture between occipital and parietal bones

lambdoidal

multiple nuclei

large size of cells means that extra nuclei are needed to drive heavy load of transcription and translation of proteins to keep cell alive and functioning

multinucleate

large size requires high rate of protein synthesis supported by high rate of gene transcription

periods of the twitch

latent, contraction, relaxation

eversion

lateral aspect of feet point up

distal lateral articulating process of femur

lateral condyle

raised area above capitulum of humerus

lateral epicondyle

the raises area above the capitulum of the humerus is the

lateral epicondyle

distal process of fibula forming outer prominence of ankle

lateral malleolus

once degraded osteoblasts can

lay down fresh bony matrix

epiphysis composition

layer of compact bone surrounds layer of spongy bones

epiphysis covered by

layer of hyalin cartilage - articular cartilage

small indentation separating ischial spine and tuberosity

lesser sciatic notch

process inferior and medial to neck of femur

lesser trochanter

process inferior and medial to the neck and femur

lesser trochanter

rounded anterior process distal to anatomical neck of humerus

lesser tubercle

rounded anterior process distal to anatomical neck of humerus.

lesser tubercle

bat shaped portion of the sphenoid bone anterior to the sella turcica

lesser wings

i band

light, isotropic region, bisected by z line

osteoprogenitor cells

line both the inner layer of periosteum and the endosteum, give rise to all osteoblasts

endosteum location

lines inner surface of compact bone and trabeculae of spongy bone

hyaline (articular) cartilage

lines the ends of bones facing one another, compression absorbing, also contains synovial fluid, slippery fluid forced out with each compression

contraction coupling

linking release of acetylcholine at the nmj to the release of calcium from the sarcoplasmic reticulum and rapid crossbridge cycling within the large myofibril mass in the muscle cell

somatomedins

liver derived hormones secreted in response to GH (most potent stimulator of cartilage, bone, and skeletal muscle growth)

class of bones having greater length than diameter

long

osteon

long pillars of hardened matrix that run lengthwise along bone, concentric and circumferential lamellae (plates)

bone shape classifications

long, short, flat, irregular

syndesmosis joint

longer collagen fibers attach bones together, amphiarthrosis and synarthrosis

long bone

longer than they are wide, serve as levers for movement

posterior boundary of false pelvis

lumbar vertebrae

stability

maintain posture by preventing unwanted movements, antigravity muscles: prevent us from falling over, stabilize joints by maintaining tension

bone forming lower jaw

mandible

lower jaw bone

mandible

the upper part of the breastbone is the

manubrium

complete thick filament

many heads projecting off the filament from both ends and in all directions around the filament

myosin molecules and thick filaments

many myosin molecules bundled together side-on and end-on to make a thick filament

process posterior to styloid process of temporal bone

mastoid

zone of hypertrophy

maturation, enlargement, blood vessel development (VEGF)

bone forming upper jaw

maxill

bone forming anterior portion of the hard palate

maxilla

bones forming upper jaw bone and parts of orbits

maxillae

canal like passageway

meatus

inversion

medial aspect of feet point up

distal medial articulating process of femur

medial condyle

raised area above trochlea of humerus

medial condyle

distal process of tibia forming inner prominence of ankle

medial malleolus

cavity within the shaft of a long bone

medullary cavity

hyperpolarization

membrane charge moves toward a more negative value

the external and internal surfaces of bone are covered by

membranes

embryonic skeleton begins as

membranes and cartilage

prominent opening on the body of the mandible

mental foramen

metacarpal articulating with proximal phalanx of thumb.

metacarpal I

instep bone articulating with proximal phalanx of little toe

metatarsal v

bones forming the instep of the foot

metatarsals

sarcoplasmic reticulum and terminal cisterns

modified form of endoplasmic reticulum; storage site for ca2+ ions

osteoporosis remodeling balance

more resorption than deposition, mass declines despite normal matrix composition

myofibrils make up

most of the cell's volume

thin filaments consist

mostly of two twisted strands of fibrous actin (f-actin)

fibrocartilage

mostly thick collagen fibers

the motor unit

motor neuron and all of the muscle cells it controls

factors that affect intensity of muscle contractions

motor unit recruitment, temporal summation, length tension relationship

movement

move from place to place; move body parts; move body contents in breathing, circulation, and digestion, in communication: speech, writing, facial expressions and other nonverbal communications

functions of skeletal muscle

movement, stability, control of openings and passageways, heat production, glycemic control

synovial joints permit a wide range of movements

movements occur within planes of space

abduction

moves limb away from midline

adduction

moves limb towards midline

ball and socket

multiaxial

movement in 3 planes of space

multiaxial

the nerve cell

muscle cell relationship and stimulation of the muscle cell

muscle structure: from macro to micro

muscle covering,

eccentric contraction

muscle lengthens as it contracts (e.g., in the biceps brachii when lowering a load)

isotonic muscle contraction

muscle tension overcomes resistance resulting in movement, tone (tension) stays constant, but length changes, concentric contraction muscle shortens as it contracts (e.g., in the biceps brachii when lifting a load)

glycemic control

muscles absorb and store glucose which helps regulate blood sugar concentration within normal range

botulism

muscular paralysis (flaccid paralysis) caused by toxin from clostridium botulinum, prevents release of ach at synaptic knobs, although toxin ingestion can be life-threatening, careful injections of it can treat spasticity (e.g., due to cerebral palsy) or can be used for cosmetic purposes (diminishing wrinkles)

organization of a sarcomere

myofilaments (thin and thick) are arranged in repeating units called sarcomeres

the ach receptor is a chemically gated ion channel that permits

na+ to enter at the nmj and this moves the motor end plate (epp) to threshold (-65mv)

bones forming upper part of the bridge of nose

nasal

constriction distal to head of radius

neck

constriction distal to the head of the radius

neck

§fluid inside cell is ____ compared to fluid outside cell

negative

icf

negative relative to the ecf

irregular bones

no distinct shape to fit into other categories

synarthrotic joint

no movement allowed

no movement

nonaxial

plane/gliding

nonaxial

rich supply of blood vessels and nerves enter through

nutrient foramen

direction of fracture

oblique (on an angle), transverse (across), spiral (twisting)

large opening in inferior region of coxal bone

obturator foramen

large opening in the inferior region of the coxal bone

obturator foramen

bone forming floor and lower rear wall of cranium

occipital

bone forming posterior inferior portion of the skull

occipital

the atlas articulates superiorly with the

occipital

rounded projections lateral to the foramen magnum that articulate with the first cervical vertebra

occipital condyles

oblique fracture

occurs at an angle across the bone

posterior process on proximal end of ulna forming point of elbow

olecranon

depression on posterior surface at distal end of humerus

olecranon fossa

posterior projection on proximal end of the ulna forming the point of the elbow

olecranon process

impacted fracture

one bone fragment is firmly driven into the marrow cavity or spongy bone of the other

each muscle fiber is supplied by

only one motor neuron

action potentials are being generated all along the sarcolemma as voltage-gated channels trigger

open in response to changes in voltage in the neighboring region of the cell

fracture classification

open vs closed, complete vs incomplete, displaced vs nondisplaced, direction

openings in the sphenoid though which optic nerves enter the orbits

optic foramina

compact bone extracellular matrix secreted by

osteoblasts

matrix is secreted by

osteoblasts

specific molecules control mineralization and prevent inappropriate mineralization, inhibited by

osteoblasts

mineralization of bone process

osteoblasts secrete collagen - minerals deposit on collagen and begin to harden matrix - kickstart so more calcium and phosphates are recruited and matrix solidifies

mature bone cells

osteocytes

chondrogenic cells differentiate into

osteogenic cells -> osteoblasts

inner layer of periosteum

osteogenic layer

structural unit of compact bone is the

osteon

decline in estrogen levels is highly correlated to

osteoporosis development

girth increases due to activity of

osteoprogenitor cells in the periosteum

bone cell types

osteoprogenitors (osteogenic), osteoblasts, osteocytes

collar of long bone

outer dense layer of compact bone

the relationship between nerve cells and muscle cells is a determinant of

overall force and level of fine tuning of force that can be produced by that muscle

bone forming posterior third of hard palate

palatine

bone forming the posterior portion of the hard palate

palatine

bone forming lateral wall of cranial vault

parietal bone

incomplete fracture

partial fracture extends only partway across the bone, pieces remain joined

central canal

passageway for blood vessels and nerves

the sesamoid bone located in front of the knee joint

patella

the superior opening os the true pelvis

pelvic inlet

protects viscera in abdominopelvic cavity

pelvis

initially the outer layer of the hyaline cartilage is surrounded by the

perichondrium

cartilage is surrounded by

perichondrium - dense irregular connective tissue layer

gomphosis joint

peridontal ligaments, collagen fibers locking tooth into socket, synarthrosis

covering of bone surface

periosteum

outer membrane of bone

periosteum

osteoblasts convert the perichondrium to the

periosteum -> forms the bone collar

pns

peripheral nervous system (peripheral nerves)

gated ion channels

permit ions passage across the membrane; this movement is electrical current and stimulates contraction of the cell

downward extending process of ethmoid

perpendicular plate

plantar flexion

phalanges point inferiorly

dorsiflexion

phalanges point superiorly

structural classifications based upon

physical structure of the joint (how they join/associate)

joint between radius and ulna allows for uniaxial movement too

pivot joint- pronation and supination

neuromuscular junction (nmj)

point of close association between the motor neuron and the muscle cell

sharpey's fibers very thick at

points of tendon/ligament attachment

other risk factors for osteoporosis

poor diet, vitamin D deficiency (low vitamin C - increased PTH), smoking, sedentary lifestyles (bone homeostasis require tension - weight bearing)

high risk for osteoporosis

post menopausal women

hyaline cartilage

primarily fine collagen fibers

diaphragm action

prime driver of inspiration

compact bone matrix

proteoglycans, collagen, etc.

organic components of bone function

provide flexibility

inorganic components of bone function

provide structure

atp should always be available in the cell

provided that it is alive and metabolism is occurring properly

zygomatic (major and minor) action

pulls corners of mouth posteriorly and superiorly (smile)

orbicularis oris action

purses and protrudes lips; puckering- kissing motion

muscle relaxation requires

qatp, and atp production is no longer produced after death, fibers remain contracted until myofilaments begin to decay

junctional folds

qinvaginations of the muscle cell membrane that serve to increase surface area at the nmj

action potential

quick event observed in a stimulated cell resulting from rapid movements of na+ and k+ across the membrane

lateral depression on ulna articulating with head of radius

radial notch

lateral bone of forearm

radius

the myosin head extends at the hinge (re-energizes)

re-positioning the actin binding sites so that another crossbridge can form with the thin filament

motor unit recruitment

recruit just a few motor units to lift a pencil, recruit many motor units to lift a suitcase, if doing external stimulation, above a certain voltage, all units are recruited, and so maximum contraction occurs (regardless of how much higher the voltage is elevated)

muscles of the abdomen

rectus abdominis, external oblique, internal oblique, transversus abdominis

marrow carrying out hematopoiesis

red

openings in spongy bone are filled with

red marrow

synovial fluid purpose

reduce friction, provide nutrients, removes waste

high mitochondrial density

reflects high metabolic demand

the neuromuscular junction (nmj)

region of close association between motor neuron and skeletal muscle cell

troponin and tropomyosin

regulatory proteins of the thin filament

ligaments

reinforce the capsule

total bone mass is

relatively constant in younger adults, areas of bone are remodeled at various rates

collagen fibers of the matrix run in opposite directions in order to

resist twisting

cartilage layers

resting zone, proliferation zone, hypertrophic zone, calcification zone, ossification zone

extension

returns the angle to baseline angle

the rapid loss of + charged k+ ions from the cell

reverses the depolarized membrane potential (back toward a more negative value and a return to a normal polarized state) - repolarization

rapid accumulation of + charged na+ ions in the cell

reverses the membrane potential (depolarization)

the pubic angle of the female pelvis is

right or obtuse

compact bone is composed of

rings of hardened matrix

spongy bone is arranged as

rods

acl

runs from anterior intercondylar area to posterior of femur lateral (intercondylar fossa), prevents anterior displacement

pcl

runs from posterior intercondylar area) to posterior of femur lateral (medial intercondylar fossa), prevents posterior displacement

the curvature formed by the sacrum and the coccyx is the

sacral

collagen fiber flexibility from

sacrificial bonds

articulation between pelvic girdle and axial skeleton

sacroiliac crest

the coxal bone articulates posteriorly with

sacrum

suture between parietal bones

sagittal

membranes and cartilage form

scaffolds for bone development

at or around the time of birth

secondary ossification centers form in the epiphyses of the bone

C cells (parafollicular cells)

secrete calcitonin, inhibits osteoclasts and promotes Ca++ excretion

osteoblasts function

secrete fresh matrix

sharpey's fibers function

secure periosteum to bone

small depression in sphenoid midline in which pituitary glands reside

sella turcica

binding sites on the actin globules for myosin heads are exposed

setting the stage for interaction between the thin and thick filaments

working muscles are an organization of many muscle cells together

several different connective tissue coverings protect and wrap cells together to form muscles and organize muscles into groups

at puberty

sex hormones induce rapid growth of bone (growth spurt)

after puberty

sex hormones slow down growth at the epiphyseal plates -> become epiphyseal lines and longitudinal growth tops

muscle cell features

shallow depression along synaptic surface captures acetylcholine which enhances likely activation of the muscle cell, large number of acetylcholine receptors packed into the muscle cell membrane at the synaptic surface, junctional folds enhance overall membrane surface and thus increase density of receptors at the synapse

synovial joints are classified based on

shape and range of motion

shin splints

sharpey's fibers pull away from matrix

suture joint

short interlocking ct fibers (sharpey's fibers), synarthrosis

denervation atrophy

shrinkage of paralyzed muscle when nerve remains disconnected

secondary ossification center

similar events occur - blood vessels invade, matrix laid down, degraded, laid down again

single twitch

single stimulation is applied, single twitch is produced, small level of force is generated

elbow joint

single synovial cavity protected by fibrous membrane and surrounded by supporting ligaments

cavity contained within skull bone

sinus

cavity within a bone

sinus

lined with mucous membrane

sinus

articulations

sites where two bones come together

structural support

skeleton is the framework of the body

open fracture (compound)

skin is broken, bone protrudes through skin, wound extends to fractured bone

closed fracture (simple)

skin is not broken

as cross bridge cycling proceeds

sliding of the thin filaments inward by the pulling action of the thick filaments leads to shortening of the sarcomere

amphiarthrotic joint

slight movement allowed

compact bone is rings of hardened matrix connected by

small passageways

canaliculi

small passageways fulled with tissue fluid and extensions of osteocytes, osteocytes connected by gap junctions

compact bone composition

smooth, homogenous, solid

ion channels are regulated

sometimes they are closed and no diffusion is permitted and sometimes they are open and the ion is moving across the membrane down its gradient, these channels are referred to as gated channels - to gate means to open

joint cavity

space between bones containing synovial fluid

tetanus

spastic paralysis caused by toxin from clostridium tetani, blocks release of inhibitory neurotransmitter in spinal cord, resulting in overstimulation of muscles, vaccination prevents this life-threatening condition

cartilage and bone are

specialized connective tissue that function in structure and support of the body

gated ion channels are

specific and regulated

control of openings and passageways

sphincters: internal muscular rings that control the movement of food, blood, and other materials within body

spongy bone structure

spicules and trabeculae, lined with endosteum, spaces filled with red marrow, no osteon structure but lamellar matrix

vertebral column encloses the

spinal cord

prominent ridge running horizontally across posterior surface of scapula

spine

sharp, slender projection that serves as the site of muscle attachment

spine

type of bone most affected by osteoporosis

spongy

type of bone composed of small spicules of bone and lots of open spaces

spongy (cancellous)

action potentials next start here and then

spread along the entire muscle cell membrane: this is a transmission of electricity across and deep into the interior of the cell

starting from the nmj, action potentials

spread outward along entire membrane surface

suture between temporal and parietal bones

squamous

sarcoplasmic reticulum (sr) and myofibrils

sr forms a loose network around each myofibril (like a loosely woven sweater sleeve)

muscle of head and neck movement

sternocleidomastoid

ribs articulate anteriorly with the

sternum

the breastbone is the

sternum

growth hormone

stimulated bone elongation and cartilage proliferation at epiphyseal plates

skeletal muscle never contracts unless

stimulated by a nerve

testosterone

stimulated osteoblasts and promotes protein synthesis promoting adolescent growth and epiphyseal closure

insulin

stimulates bone formation, significant bone loss occurs in untreated diabetes mellitus

estrogen

stimulates osteoblasts and adolescent growth, prevents osteoporosis

estrogen role in bone remodeling

stimulates osteoblasts, inhibits osteoclasts

fused tetanus process

stimuli arrive so frequently that there is no evidence of relaxation, crossbridge cycling peaks with maximum sarcomere shortening, muscle will fatigue as cell cannot produce sufficient atp to maintain intensity of crossbridge cycling for extended period of time at 100% wave summation, as atp stores are depleted, cell will lose tension

close association of sr with the myofibrils

stored calcium is surrounding all of the contractile protein components

bone remodeling along lines of

stress

the skeletal system performs multiple functions

structural support, movement, protection, blood cell formation, mineral storage, acid base and electrolyte balance, fat storage

pointed medial projection at distal end of ulna

styloid process

groove or furrow

sulcus

the superior and vertebral borders the scapula join at the

superior angle

bone function

support, resist compressive and pulling forces (stessors)

cartilage function

support, resist compressive forces (stressors)

opening above each orbit

supraorbital foramen

bone remodeling occurs at

surface of periosteum and endosteum

common site of arm fractures

surgical neck

cranial articulation

suture

axon terminal

swollen end of nerve fiber, contains synaptic vesicles with acetylcholine (ach)

the articulation joining the two pubic bones is the

symphysis pubic

nerve cell terminal end

synaptic knob ("enlarged foot")

types of functional joints

synarthrotic, amphiarthrotic, diarthrotoc

an action potential propagates down the length of the entire cell membrane

t-tubules as well so the entire cell from outside to inside becomes electrified

tarsal bone between tibia and calcaneus

talus

hyaline cartilage and fibrous membranes serve as

templates for bone formation

bone inferior to the parietal bone

temporal

forms movable joint with mandible

temporal

muscles of mastication

temporalis, masseter

only movable joint in the skull

temporomandibular joint

key regulator of bone remodeling

tension

contributor to the density of bone

tension (weight bearing)

muscle tension

tension is the force generated when a muscle is stimulated to contract, lab experiments measure tension and graph it (myogram)

when tension overcomes resistance of the load

tension levels off

relaxation requires

termination of nerve cell stimulation and a return to resting conditions inside the muscle cell

relaxation process

termination of nerve signal and ach release from motor neuron (no more neurotransmitter release) hydrolysis (degradation) of ach by acetylcholinesterase located in the synaptic cleft; enzyme clears the chemical quickly from the extracellular space....... closure of ach receptor causes cessation of end plate potential so no further action potential generation in the muscle cell closure of ca2+channels in sarcoplasmic reticulum and ca2+will be taken back up by the sarcoplasmic reticulum by active ca2+ transporters (calcium is cleared out of the sarcoplasm) as ca2+ levels decline in the sarcoplasm, troponin changes shape and re-positions tropomyosin back along the thin filament blocking the myosin binding sites; cross bridge cycles stop muscle returns to resting state

each channel type gates at a different voltage

that means different ions move directionally across the membrane at different times under different conditions

resting membrane potential (rmp) created by

the action of the na+/k+ atpase

muscles produce tension/force when they contract

the amount of force produced can be varied based upon the demand placed on the muscle

neuromuscular junction

the area where the enlarged terminal end of the neuron comes in close association with the sarcolemma of the muscle cell

the border of each sarcomere

the border of each sarcomere

major articulation points in the elbow joint

the capitulum of the humerus and head of the radius, the trochela of the humerus and trochlear notch of the ulna, the head of the radius and the radial notch of the ulna

chemically-gated ion channel will stay open as long as

the chemical remains present in the synaptic cleft

calcitonin aids in

the control of bone remodeling by maintaining homeostatic levels of Ca++ in the blood, decrease blood Ca++ levels

initial stimulus

the delivery of acetylcholine to the muscle cell membrane and how it moves the membrane toward threshold to trigger an action potential

myosin head degrades atp (breaks a phosphate bond) and produces adp + pi

the energy released is use to change shape at the hinge

if these channels are gating open to induce an action potential in this region

the flow of ions across the membrane here will move the neighboring membrane area to threshold and that will trigger these voltage gated ions channels in this area to gate open

linear fracture

the fracture is parallel to the long axis of the bone

transverse fracture

the fracture is perpendicular to the long axis of the bone

temporal (wave) summation

the frequency of stimulation can influence tension development by a muscle fiber, repetitive stimulation of a fiber produces contractions of longer duration and greater tension than a single twitch

the trigger that opens the channel is called

the gating stimulus

myosin changes shape at the hinge

the head flexes inducing the power stroke

immediately upon binding to actin, myosin changes shape at the hinge

the head flexes relative to the tail, since it is gripping the thin filament this means it pulls the thin filament toward the midline of the thick filament (the thin filament slides inward), this movement is called the power stroke, the myosin head releases adp and pi when it completes the power stroke

repolarization

the membrane has returned to a state of polarization following a depolarization event

acetylcholine binds to its receptor on

the muscle cell membrane

as sarcomeres shorten

the myofibrils will shorten...and the muscle cell shortens

in the presence of atp

the myosin head will quickly release from actin

rmp is generated primarily by

the na+/k+ atpase pumps

eventually the na+ and k+ channels close

the na+/k+ atpase returns the na+ and k+ ion gradients to rest conditions. this means the cell is quickly primed to fire another action potential ....within milliseconds.

synaptic cleft

the narrow gap between axon terminal and sarcolemma

chemically gated ion channels are concentrated at

the neuromuscular junction and are critical for the nerve cell to activate the muscle cell

strength of a muscle and the direction of its pull are determined partly by

the orientation of its fascicles

nondisplaced fracture

the portions of bone are still in correct anatomical alignment

the banding pattern of the sarcomere

the positions of thin and thick filaments give rise to alternating i-bands and a-bands

the striations of skeletal muscle are due to

the precise organization of thin and thick filaments (called myofilaments) in the myofibrils, a pattern that is repeated over and over again along the length of the entire cell

blood vessels invade

the primary ossification center and bring osteopregenitor cells

if threshold is reached for gating of fast voltage-gated na+ channels

the regional membrane will fire an action potential and that will trigger activation of electrical impulse transmission across the entire muscle cell

motor neuron releases acetylcholine at

the synapse

length-tension relationship

the tension a muscle produces depends on its length at the time of stimulation

the myofibril is comprised of many sarcomeres in a series

the z-discs connect each neighboring sarcomere along the entire length

depolarization

there has been a change in charge inside the cell toward a less negative (or more positive value)

action potentials shoot down the t-tubules

these electrical impulses shock the flanking sarcoplasmic reticulum (terminal cisterns)

each strand is a necklace of hundreds of actin globules

they link together to create f-actin; two f-actin strands twist together to form the base of the thin filament

troponin and tropomyosin function

they regulate the interaction between thin and thick filaments and therefore control the transition between the at-rest and contractile state of the muscle cell

narrowing (or disappearance) of h zone and i band

thick and thin filaments remain the same length but slide past each other

fusiform muscles

thick in the middle and tapered at each end

a sarcomere is a precise overlapping array of

thin and thick filaments

binding of myosin head to actin is a crossbridge

thin and thick filaments are attached (thick is gripping thin)

flat bone (sesamoid)

thin and usually curved, forms in tendon

epiphyseal line

thin plate of compact bone in adults, remnant of epiphyseal plate, disc of hyaline cartilage that allows bone to grow during childhood

bone growth from

thin plates of cartilage called epiphyseal plates

stimulation of the muscle cell will trigger release of calcium from the sarcoplasmic reticulum

this is the trigger for interaction of thin and thick filaments

a single cross-bridge cycle is not sufficient to produce a robust contraction of the muscle

this process has to repeat many times over to get shortening of the muscle

binding site for myosin is covered in

this thin filament

facets for articulation with the ribs are found on the f

thoracic vertebrae

cone shaped enclosure forming shield protecting heart and lungs

thorax

ulnar collateral ligament

three band of strong flexible tissue attach the humerus to the ulna - anterior band (strongest), posterior band, transverse band

femur articulates distally with

tibia

medial bone of the lower leg

tibia

the fibula articulates proximally with

tibia

midline projection anterior and inferior to tibial condyles

tibial tuberosity

mineralization of bone is a

tightly regulated process involving multiple organ systems

latent period

time after stimulus but before contraction begins, no change in tension; ca2+ levels are still low in the sarcoplasm

relaxation period

time when tension is decreasing to baseline, begins with release of crossbridges, no more action potentials; ca2+ is being removed from sarcoplasm, generally lasts a little longer than contraction period

contraction period

time when tension is increasing; action potentials have triggered release of ca2+, begins as power strokes pull thin filaments; tension rises quickly as crossbridge cycling proceeds

tropomyosin is pulled

to a slightly different position

rapid diffusion of na+ and k+ ions across the membrane through regulated ion channels allows the muscle cell

to activate and trigger internal events that lead to contraction

trabeculae arrangement

to resist stress and compression

spongy bone lattice of rods

trabeculae

the axon of the spinal motor neuron

transmits an electrical signal to muscle cells located within the target muscle

terminal cisterns combine in twos with central t-tubule to form

triads

voltage-gated ca2+ channels

trigger open

ca2+ interacts with myofilaments

triggering contraction

the myosin head binds a fresh molecule of atp

triggers its release from actin

very large, usually irregularly shaped pricess

trochanter

condyle on humerus that articulates with the ulna

trochela

condyle on humerus that articulates with ulna

trochlea

calcium is bound by

troponin in the thin filament

(t/f) the clavicle articulates with the acromion process of the scapula

true

(t/f) the cuboid is a tarsal bone

true

(t/f) the hamate is a carpal bone

true

(t/f) the head of the humerus articulated with the glenoid cavity of the scapula

true

(t/f) the proximal phalanx of the thumb articulates with metatarsal I

true

(t/f) the radius articulates with the ulna

true

small rounded process serving for muscle attachment

tubercle

midline projection from anterior surface just below tibial condyles

tuberosity

t tubule

tubular extension of the cell membrane that runs directly into the interior of the large muscle cell

supination

turn palm anteriorly

protonation

turn palm posteriorly

impacts capable to breaking bone

twisting or blunt force

each myosin molecule has

two heads and two intertwined tails

joint capsule

two layered covering for the joint, fibrous layer of dense irregular ct, synovial layer of loose ct produces synovial fluid

wave summation

two stimulations are applied in close succession, the cell begins to contract after stimulus #1 but does not get to fully relax before stimulus #2 hits the cell, the force produced by stimulus #2 adds on to the force from stimulus #1 and reaches a higher value, higher force reflects higher level of ca2+ in the sarcoplasm....too little time to clear it all when stimulations come close together in time

triad

two terminal cisterns flanking one t-tubule: one triad is located at each a-i band junction; carries electrical current deep into muscle fiber

the muscle cell is electrically charged at rest due to

unequal pumping of positively charged ions across its membrane even at rest

hinge

uniaxial

movement in one plane of space

uniaxial

parallel muscles

uniform width and parallel fascicles

net diffusion direction of the ion moving through the channel depends

upon the concentration gradient only for that ion; so na+ will move directionally according to its gradient only, k+ according to its gradient, etc.

myasthenia gravis details

usually occurs in women between 20 and 40, muscle fibers remove receptor clusters from the sarcolemma by endocytosis, fiber becomes less and less sensitive to ach, effects usually first appear in facial muscles, drooping eyelids and double vision, difficulty swallowing, and weakness of the limbs, strabismus: inability to fixate on the same point with both eyes

encases spinal cord

vertebrae

center opening in each vertebra is the

vertebral foramen

bone tissue is

very metabolically active and is continuously remodeling

as membrane potential moves toward threshold at the nmj

voltage gated na+ channels in the region will open at -65 mv and an action potential will be triggered in the surrounding membrane region

when the membrane reaches -65mv

voltage-gated na+ channels open in the nmj and action potentials form radiating outward from the nmj along the sarcolemma and down the t tubules

bone forming posterior and inferior nasal septum

vomer

thin bone on median line in nasal cavity

vomer

unpaired face bone in nasal cavity

vomer

mineralization occurs and osteoblasts are

walled off into lacunae and become osteocytes

stressors

weight bearing or muscle pull

since the muscle fibers are spread out within the muscle and all contract together

when the motor neuron activates the motor unit will produce a weak general contraction over wide area

the muscle fibers of the same motor unit

will all contract in unison

chemically-gated ion channel is specific

will permit a particular ion to diffuse across the membrane

incidental bones developing in the sutures of the skull

wormian

to get maximum force production from muscle

would want 100% motor unit recruitment

the lower part of the breastbone is the

xiphoid process

adipose tissue stored in a medullary cavity

yellow marrow

fat storage

yellow marrow

bone forming inferior lateral surface of eye orbit

zygomatic

bone forming prominence of cheek

zygomatic

bones commonly called cheekbones

zygomatic

rmp in skeletal muscle cells

~ -90 m

spongy bone replaces every

~3-4 years

bone grows in length throughout life until

~puberty

each actin globule (bead) has a myosin binding site

§to which myosin heads attach during contraction (the myosin heads will attach to the actin beads of the thin filament during muscle contraction)

heads are

•angled off of the tails and can bend at a hinge location (similar to the way you can bend your closed fist toward your forearm when your arm is extended...)


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