A & P Test #3
Most bones formed by intramembranous ossification are the long, short, and irregular bones. T or F
Cranial bones develop _______
within fibrous membranes (membrane model)
What kind of tissue is the forerunner of long bones in the embryo?
Epiphysis usually remain cartilage through birth. Ossification of these epiphyses________
is produced by secondary ossification centers
For intramembranous ossification to take place, which of the following in necessary?
an ossification center forms in the fibrous connective tissue
Steps of intramembranous ossification:
1. Oss. centers appear
2. Osteoblasts secrete osteoid, then calcifies
3. Woven bone and periosteum form
4. Lamellar bone replaces woven bone
The process of bones increasing WIDTH is ______
The process of bones increasing LENGTH is _______
Bone remodeling is similar to _____
Bones are constantly undergoing resorption for various reasons. Which of the following cells acomplishes this process?
During prenatal development, most bones beneath the skull form by a process known as ________
Which of the following is NOT a step in intramembranous ossification?
Destroy and remove old cartilage
_____begins around week 8 of development and continues until a person stops growing?
Growth in the length of long bones during infancy and youth is through ___
Interstitial growth (longitudinal) of the epiphysial plates
On average, longitudinal bone growth ends at 21 in males and 18 in females. T or F
Which of the following concerning bone remodeling is not true?
All true! (most adult bone changes, occurs between periosteum and bone, occurs between endosteum and bone, occurs in osteogenic layer)
12th week of endochondral ossification, cavity consisting on nutrient artery/vein, nerve fibers, red marrow, osteoblasts, and osteoclasts
Stages of a healing bone fracture:
2. Fibro. cartilage callus formation
3. Bony callus
4. Bone remodeling
The ammount of movement permitted in a particular joint is the basis for the structural classification of joints. T or F
False - Functional classificaion
Articulations permitting slight degrees of movement
Articulations permitting no movement
Articulations permitting all movement
A fibrous joint that is a peg in socket joint
On the basis of structural classification, which joint type below is d.f.c.t?
Hinge joints permit movement in two planes. T or F
False - move in one plane
Which is true about synovial fluid in joints?
It contains hyaluronic acid
Multiaxial joints of the body include:
Hip and shoulder
Conn. tissue sacs lined with synovial membranes that act as cushions in places where friction develops
Attatched to the immovable or less movable bone
Attatched to the more movable bone
During contraction, a skeletal muscle insertion usually moves toward the origin. T or F
Muscle group that works with and assists the action of a prime mover
Which connective tissue sheath surrounds fascicles?
Order of conn. tissue on muscles:
Muscle fiber - endomysium - fascicles - perimysium - bundles - epimysium
a sheetlike indirect attatchment to a skeletal element
What serve as a trigger for muscle contraction by binding to troponin to remove tropymyosin off binding sites?
Calcium ions, Ca2+
What diffuses across the membrane, binds to receptors associated with chemically gated ion channels, untimately resulting in local depolarization of membrane?
The major function of the sarcoplasmic reticulum in mm contraction is ____
To regulate intracellular calcium concentration
Function of T tubules
to allow the AP deep into the fiber
A sarcomere is the distance between two _____
The thicker filaments are the ____filaments
The ____contains only the actin filaments
Both actin and myosin are found in the ____
The myosin filaments are located in the ____
Sequence for mm contraction:
motor neuron AP - neurotrans release - mm cell AP - release of Ca+ from SR - ATP driven power stroke - sliding myofilaments
The sliding filament model of contraction involves_____
Actin and myosin sliding past eachother and partially overlapping
Rigor mortis occurs because
no ATP is availible to release attatched actin and myosis molecules
What prevents ACh in the synaptic cleft from continuing to stimulate contraction?
Acetylcholinesterase destroying the ACh