Biology Exam 2 (Chapters 8-14) Flashcards
The process of dissolving bone and returning its minerals to the bloodstream is known as
reabsorption
Synthesized by the combined action of the skin, kidneys, and liver, _________ promotes bone resorption but is also necessary for bone deposition.
calcitriol
Chondrocytes multiply in the zone of _________ of the metaphysis.
cell proliferation
Osteogenic cells are bone stem cells that differentiate into osteoblasts and osteoclasts.
False
The ___________ is an example of bone as an organ; ___________ bone is an example of bone as a tissue.
femur; spongy
In endochondral ossification, the precursor connective tissue is __________, which is replaced by bone.
hyaline cartilage
The spaces found within the concentric lamellae are called __________, and they contain __________.
lacunae; osteocytes
Which of the following tissues is not found as part of a long bone?
Transitional epithelium
A radiograph (X-ray) of a child’s hand will show epiphyseal lines.
False
Which of the following is the correct sequence of events in the healing of a bone fracture?
Hematoma formation → soft callus formation → hard callus formation → bone remodeling
Spicules and trabeculae are found in __________.
spongy bone
Intramembranous ossification is common in children, whereas endochondral ossification is typical in young adults.
False
Achondroplastic dwarfism is a hereditary condition, in which the long bones of the limbs fail to elongate normally because of reduced hyperplasia and hypertrophy of cartilage in the _________.
epiphyseal plate
Osteoporosis is more common in elderly females because of the lack of _________.
estrogen
Blood Ca2+ deficiency stimulates __________ secretion, which leads to __________.
parathyroid hormone; increased osteoclast activity
Red bone marrow is important in the production of new bone cells.
False
If a thyroid tumor secreted an excessive amount of calcitonin, we would expect ___________.
an elevated level of osteoblast activity
Wolff’s law of bone explains the effect of __________.
mechanical stress on bone remodeling
Which one of the following bone cells would have the greatest number of lysosomes?
Osteoclasts
Which of the following is an inorganic component of the bone matrix?
Hydroxyapatite
The shoulder is the only multiaxial, ball-and-socket joint in the human body.
False
Most of the bones of the skull are connected by immovable joints called __________.
sutures
Why does an adult not have as many bones as a child?
Some separate bones gradually fuse with age.
All the bones below belong to the axial skeleton, except the __________, which belongs to the appendicular skeleton
scapula
Which of the following is the most stable joint?
coxal joint
The most movable joints are ___________ joints.
synovial
Bursae are structures associated with fibrous, cartilaginous, and synovial joints.
False
A(n) __________ is a sac of fluid associated with a synovial joint.
bursa
Which of the following structures prevents knee hyperextension?
The anterior cruciate ligament (ACL)
A meniscus is a type of bursa seen in the space between the femur and tibia.
False
Which of the following is the largest and most complex diarthrosis in the body?
the knee
When you walk up the stairs, your hip and knee joints _________blank to lift your body weight.
extend
A monoaxial joint, like the elbow, is capable of which one of the following movements?
Flexion and extension
The metacarpophalangeal joints at the base of the fingers are ___________ joints.
condylar
The jaw joint is the articulation of the __________ and the __________.
mandible; temporal bone
Radial (lateral) and ulnar (medial) collateral ligaments restrict side-to-side movements of the __________ joint.
elbow
The joint between the L2 and L3 vertebrae is a
symphysis
Which of the following structures is not found in the shoulder?
the radioulnar ligament
The __________ bursa is not an accessory structure of the glenohumeral joint.
subpatellar
The rectus femoris is an example of what muscle shape?
Pennate
Muscle fibers are arranged in bundles called ___________.
fasicles
Which term refers to a muscle that prevents a bone from moving during an action?
Fixator
Which of the following is not a function of the muscular system?
Secretion
What term best describes the relationship between the pronator quadratus and supinator?
Antagonists
The antagonist to the triceps brachii is the _________blank.
biceps brachii
Which of the following describes muscular tissue emerging directly from bone rather than being separated from it by an obvious tendon?
direct attachment
Which connective tissue layer bundles muscle fibers together into fascicles?
Perimysium
Which of the following is not a characteristic of a muscle cell?
Plasicity
Which of the following contains overlapping thick and thin filaments?
A band
A myofilament that runs through the core of a thick filament and anchors it to a Z disc is called a(n)
elastic filament
A skeletal muscle fiber (cell) contains a single nucleus.
False
Bony (synostosis)
immobile joint formed when the gap between two bones ossifies, and they become a single bone
Fibrous (synarthrosis)
a point at which adjacent bones are bound by collagen fibers that emerge from one bone, cross the space between them and penetrate into the other
Three types of fibrous joints
Sutures- fibers are very short and allow for little or no movement
Gomphoses- fibers are very short and allow for little or no movement
Syndesmoses-fibers are longer, and the attached bones are more mobile
Cartilaginous (amphiarthrosis)
two bones are linked by cartilage
Two types of cartilaginous joints
Synchondroses- a joint in which the bones are joined by hyaline cartilage
Symphyses- two bones are joined by fibrocartilage
Synovial (diarthrosis)
- a point where two bones are separated by a narrow, encapsulated space filled with synovial fluid; freely mobile
Ball-and-socket joints
i.e, the shoulder and hip joints (the only multiaxial joints in the body); one bone has a smooth hemispherical head that fits into a cuplike socket on the other
Condylar (ellipsoid) joints
exhibit an oval convex surface on one bone that fits into a complementary-shaped depression on the other (i.e, the radiocarpal joint of the wrists); biaxial joints, capable of movement in two planes
Saddle joints
both bones have a saddle-shaped surface that is concave in one direction (front-rear) and convex in the other (left-to-right); biaxial; sternoclavicular joint
Plane (gliding) joints
bone surfaces are flat; adjacent bones slide over each other and have limited movement, i.e, carpal bones of the wrist; biaxial
Hinge joints
monaxial joints, moving freely in one plane with very little movement in any other, like a door hinge, i.e, elbow and knee
Pivot joints
monaxial joints in which a bone spins on its longitudinal axis like a bicycle wheel spinning on its axle; i.e, radioulnar joint
Functions of Muscles
Movement
Stability
Control of body openings and passages
Heat production
Hormone secretion
Glycemic control
Endomysium
thin sleeve of loose connective tissue that surrounded each muscle fiber
Epimysium
fibrous sheath that surrounds the entire muscle
Perimysium
thicker connective tissue sheath that wraps muscle fibers together in bundles called fascicles
Fascia
sheet of connective tissue that separates neighboring muscles or muscle groups from each other
Fusiform muscles
thick in the middle, with fascicles converging on each tapered end (i.e, biceps brachii)
Parallel muscles
fairly uniform width and parallel fascicles (i.e, sartorius of the thigh)
Triangular muscles
fan-shaped muscle that is broad at one end with fascicles converging on the other, narrower end (i.e, pectoralis major in the chest)
Pennate muscles
feather-shaped; fascicles insert on a tendon that runs the length of the muscle (i.e, deltoid of the shoulder)
Circular muscles
have fascicles in rings around certain body openings and passages. When they contract, they constrict the opening and tend to prevent the passage of material through it (i.e, external urethral)
Extrinsic muscles
muscles that act upon a designated organ or region, such as the hand, but arise from another region such as the forearm
Intrinsic muscles
any muscles that are contained entirely within a region of interest
Prime mover (agonist)
the muscle that produces most of the force during a particular joint action
Synergist
the muscle that aids the prime mover
Antagonist
the muscle that opposes the prime mover
Fixator
the muscle that prevents a bone from moving
Excitability (responsiveness)
when stimulated by chemical signals, stretch, and other stimuli, muscle cells respond with electrical changes across the plasma membrane
Conductivity
simulation of a muscle cell produces more than a local effect; sets off a wave of excitation that travels rapidly along the cell and initiates processes leading to contraction
Contractility
shorten substantially when stimulated, which enables them to pull on bones and other organs to create movement
Extensibility
the ability to stretch again between contractions; most skeletal muscle cells can stretch to as much as three times their contracted length
Elasticity
when a muscle cell is stretched and then released, it recoils to a shorter length
Sacrolemma
plasma membrane of a muscle fiber
Has tubular infoldings called transverse (T) tubules, which penetrate through the cell and emerge on the other side
Sacroplasm
cytoplasm of muscle fiber; contains an abundance of glycogen and myoglobin
Myofibrils
occupy sarcoplasm; long protein cords that extend the entire length of the cell
Myofilimants
each myofibril is a bundle of parallel proteins called myofilaments
Sarcoplasmic reticiulm (SR)
Forms a network around each myofibril
Has dilated end sacs called terminal cisterns, which cross the muscle fiber from one side to the other
Thick filaments
15 nm in diameter
Made of several hundred molecules of a motor protein called myosin, each myosin molecule has a shaftlike tail and a double globular head
Thin filaments
7 nm in diameter
Composed of two intertwined strands of a protein called fibrous (F) actin, a string of subunits called globular (G) actin
Each G actin has an active site that can bind to the head of a myosin molecule
Has molecules of another protein called tropomyosin
When a muscle fiber is relaxed, each tropomyosin blocks the active sites of G actins and prevents myosin from binding to them
Each tropomyosin molecule has a smaller, two-part calcium-binding protein called troponin bound to it
Elastic filaments
1 nm in diameter
Made of a huge springy protein called titin
Run through the core of each thick filament and anchor it to structures called the Z disc at one end and M line at the other
Titin stabilizes the thick filament, prevents overstretching, and recoils like spring after a muscle is stretched
