The axial skeleton is the basic framework of the body, consisting of the ____________ , _____________, and _____________.
Skull
Vertebral column
rib cage
Cartilage
composed of firm but elastic matrix called chondrin
chondrin is secreted by specalized cells called chondrocytes
cartilage is the principal component of embryonic skeletons in higher animals - hardens and calcifies into bone
Cartilage reamins in external ear, nose, walls of the larynx, and trachea, and skeletal joints contain cartilage
most cartilage is avascular - contains no blood or lymph vessels, and is devoid of nerves
*receives nourishment from capillaries located in nearby CT and bone via diffusion through the surrounding fluid.
Most cartilage is avascular, containing no blood or lymph vessels, and is devoid of nerves.
A. True
B. False
True
Cartilage receives nourishment from capillaries located in nearby CT and bone via _______ through surrounding fluid.
Diffusion
_______________, also called cancellous bone, consists of interconnecting lattice of bony spicules called ______________.
Trabeculae
______________ bone marrow is inactive and infiltrated by adipose tissue.
Yellow bone marrow
_____________ is involved in blood cell formation.
Red bone marrow
The bones of the appendages are called _____________.
Long bones
The shaft of the long bone is called a _________________.
Diaphysis
The dilated ends of long bones are called epiphyses
The diaphysis is composed primarily of __________________.
Compact bone surrounding a cavity containing bone marrow.
The ______________ are composed of spongy bone surrounded by a thin layer of compact bone.
Epiphyses
The ____________________ is a disk of cartilaginous cells separating the diaphysis from the epiphysis, and is the site of longitudinal growth.
epiphyseal plate
A fibrous sheath called the _________________ surrounds the long bone, and is the site of attachment to muscle tissue.
Periosteum
Some periosteum cells differentiate into ____________________.
Bone-forming cells
Compact bone is composed of dense, hardened bone matrix, which contains both ___________ and _____________ components.
Organic and Inorganic components
In compact bone, the organic components include ______________.
Proteins: collagen fibers, glycoproteins
In compact bone, inorganic components include _________________.
calcium, phosphate, hydroxide (which combine and harden to form hydroxyapatite crystals)
sodium, potassium, magnesium ions
The association of __________ and ____________ gives bone its characteristic strength
hydroxyapatite crystals and collagen fibers
The bony matrix is deposited in structural units called ____________, also known as Haversian systems.
Osteons
Each osteon consists of a microscopic channel called a _________________.
Haversian canal - surrounded by a number of concentric circles of bony matrix called lamellae
The Haversian canal is surrounded by a number of concentric circles of bony matrix called _____________.
Lamellae
There are _____________, ________________, and _____________ in the Haversian canals, vascularizing and innervating bone tissue.
Blood Vessels
Nerve fibers
Lymph
Radiating from each lacuna are a number of minute canals called __________________.
Canaliculi
The _____________ interconnect with each other and with Haversian canals, allowing exchange of nutrients and wastes.
canaliculi
________________ synthesize and secrete organic constituents of the bony matrix.
Osteoblast - form bone
*once they are surrounded by their matrix, they mature into osteocytes
________________ are large multinucleated cells involved in bone resorption (destroy bone!)
Osteoclasts
Bone formation occurs by either ___________________ or by ____________________.
Endochondral ossification
Intramembranous ossification
In _____________________, existing cartilage is replaced by bone.
Endochondral ossification
Long bones arise primarily through ______________________.
Endochondral ossification
In ________________________, mesenchymal (embryonic, undifferentiated) connective tissue is transformed into and replaced by bone.
Intramembranous ossification
During __________________, inorganic ions (i.e. calcium and phosphate) are absorbed from the blood for use in bone formation.
Bone reformation
During ___________________, inorganic ions (i.e. calcium, phosphate) are released into the blood.
Bone resorption (degradation)
______________, and hormones, ___________ and ______________, are all involved in the regulation of bone remodeling (forming, and destroying).
Vitamin D
Parathyroid hormone
Calcitonin
The freely movable _________ joints, the two bones are separated by a cavity.
Synovial joints
An example of a synovial joint is ______________.
the knee.
Synovial joints are subject to _____________.
Arthritis
______________ ease friction between tendons and ligaments and between tendons and bones.
Bursae
The knee and elbow are _______________ because they largely permit movement in one direction.
Hinge joint
knee-synovial joint
_____________ joints allow movement in all planes and even rotational movement.
Ball and socket
examples: ball of femur, shoulder
The skeletal muscle is innervated by the __________________.
Somatic nervous system
The cytoplasm of a muscle fiber is called _____________.
Sarcoplasm
The cell membrane of a muscle fiber is called the ____________________.
Sarcolemma
The __________________ is capable of propagating an action potential, and is connected to a system of transverse tubules (T system) oriented perpendicularly to the myofibrils.
Sarcolemma
The __________________ provides channels for ion flow throughout the muscle fibers, and can also propagate an action potential.
T system
Skeletal muscles can be characterized as either red or white.
A. True
B. False
True
Red skeletal muscle fibers are abundant in ___________ content, and _____________.
Myoglobin - store oxygen
mitochondria
_______________ derive their energy from aerobic respiration and are capable of sustained and vigorous activity.
Red skeletal muscle fibers : "slow-twitch fibers"
___________________ contain less myoglobin and fewer mitochondria.
White skeletal muscle fibers
________ skeletal muscle fibers are anaerobic.
White fibers
Which of the following has a greater rate of contraction?
A. White skeletal fibers
B. Red skeletal fibers
White skeletal fibers
Which of the following fatigues more easily ?
A. White skeletal muscle fibers
B. Red Skeletal muscle fibers
white fibers
The ______________ is composed of thin and thick filaments.
Sacromere
The thin filaments of the sacromere are the ____________.
Actin filaments
Actin filaments are associated with two proteins: _________________, ________________.
troponin
tropomyosin
The thick filaments are composed of organized bundles of ____________.
Myosin molecules
*each myosin molecule has a head region and a tail region.
In the sacromere, the ________________ define the boundaries of a single sacromere and anchor the thin filaments.
Z lines
______________ runs down the center of the sacromere.
M line
In the sacromere, the ___________ is the region containing thin filaments only.
I band
In the sacromere, the _______________ is the region containing thick filaments only
H zone
In the sacromere, the _______________ spans the entire length of the thick filaments and any overlapping portions of the thin filaments.
A band.
During skeletal muscle contraction, the ______________ is not reduced, while the H zone and are reduced.
A band. a
During skeletal muscle contraction, the ____________, and ___________ are reduced in size.
H zone, and I band
_________________ break down ATP and form cross bridges that attach to and pull the actin filaments toward the center of the sacromere.
Myosin filaments
Muscle fibers rely on _______________, a storage form of high-energy phosphate for energy.
creatine phosphate. - cannot participate directly in muscle contraction.
It anaerobically regenerates ATP by :
creatine-P + ADP -------> ATP + creatine
*this is the speediest energy source available to muscles.
Muscle contraction is stimulated by a message from the _________________ sent via a motor neuron.
Somatic nervous system
During muscle contraction, the sarcolemma of the muscle fiber is called the _____________________.
Neuromuscular junction
________________ of the motor neuron results in the release of neurotransmitters from the nerve terminal.
Depolorization
*The neurotransmitter diffuse across the synaptic cleft and binds to special receptor sites on the sarcolemma.
*If enough of these receptors are stimulated, the permeability of the sarcolemma is altered and an action potential is generated.
During muscle contraction, once an action potential is generated, it is conducted along the ____________, and the ____________, and into the inferior of the muscle fiber.
Sarcolemma, T system
During contraction, the generation of the action potential causes the ______________ to release Ca2+ into the sarcoplasm.
sarcoplasmic reticulum
The Ca2+ binds to the ______________.
a. troponin
b. tropomyosin
troponin
ATPase Activity
5 steps:
1. resting stage - ATP is hydrolyzed when myosin head is unattached
2. Ca2+ binds to troponin; myosin binds to actin
3. powerstroke occurs; sacromere contracts
4. ADP and P are released
5. New ATP binds to myosin, causing detachment of myosin from actin;
Relaxation
What is the function of Ca2+ in muscle contraction?
Individual muscle fibers generally exhibit an ____________ response.
all or none response - only a stimulus above threshold value can elicit contraction.
The strength of the contraction of a single muscle fiber cannot be increased, regardless of the strength of the stimulus.
A. true
b. false
true
Whole muscle exhibits an all or none response.
a. true
b. false.
false
*although there is a minimal threshold value needed to elicit a muscle contraction, the strength of the contraction can increase as stimulus strength is increased by involving more fibers.
A ______________________ is reached when all the fibers have reached the threshold value and the muscle contracts as a whole.
Maximal response
__________ refers to the continual low-grade contractions of the muscle, which are essential for both voluntary and involuntary muscle contraction.
Tonus
*Even at rest, muscles are in a continuous state of tonus
A ________________ is the response of a single muscle fiber to a brief stimulus at or above the threshold stimulus.
Simple twitch
A simple twitch consists of 3 periods:
1. ________________
2. ________________
3. ________________
1. latent period
2. contraction period
3. relaxation period
During a simple twitch, the time between stimulation and the onset of contraction is the ___________ period.
Latent period
During the ____________ period in a simple twitch, the action potential spreads along the sarcolemma and Ca2+ ions are released.
latent period
Following the contraction in a simple twitch, there is a brief relaxation period in which the muscle is unresponsive to stimulus, this is known as the ______________.
Absolute refractory period.
Following the absolute refractory period in a simple twitch, a _____________ occurs, during which a greater than normal stimulus is needed to elicit a contraction.
relative refractory period
When the fibers of a muscle are exposed to a very frequent stimuli, the muscle cannot fully relax.
A. true
B. false
true
*the contractions begin to combine, becoming stronger and more prolonged. This is known as frequency summation.
A tetanus contraction is stronger than a simple twitch of a single fiber.
a. true
b false.
true
*If tetanization is prolonged, the muscle will begin to fatigue
Smooth muscle is innervated by ________________.
Autonomic nervous system
_____________ possess one centrally located nucleus.
Smooth muscle
Smooth muscles also contain actin and myosin filaments.
a. true
b. false
true
*however, these filaments lack the organization of skeletal sarcomeres; thus, lacking striations.
All muscle contractions by skeletal, smooth, and cardiac require Ca2+ for contraction.
a. true
b. false
true
____________ muscle contains many nuclei per cell.
Skeletal muscle
Smooth muscle contractions are slower, and are capable of being sustained longer than skeletal muscle contractions.
a. true
b. false
true
________________ muscle typically have both inhibitory and excitatory synapses that regulate contraction via the nervous system.
Smooth muscle
_______________ muscle also have the property of reflexively contracting without the nervous stimulation; this is called myogenic activity.
Smooth muscle
*also cardiac muscle !!!!!!! has myogenic activity
Like skeletal muscle, ____________ muscle have actin and myosin filaments that are arranged in sacromeres, giving the striation look.
Cardiac
___________ muscle contains 1-2 nuclei (centrally located) per cel.
Cardiac
Cardiac muscle is innervated by the _________________.
autonomic nervous system
*cardiac muscle is also myogenic - has the property of reflexively contracting without nervous stimulation
______________ has a high O2 affinity.
myoglobin -binds to O2 from the bloodstream and holds onto it.
*During strenuous exercise, when muscle cells rapidly run out of available O2, myoglobin releases its O2.
*If the oxygen supply to muscles become insufficient to meet its energy standards, the muscle obtains additional energy via anaerobic respiration, resulting in the build-up of hte lactic acid.
Connective Tissue:
________________ binds epithelium to underlying tissues and is the packing material that holds organs in place.
