Anatomy and Physiology Chapters 4-7
skeletal system
composed of bones, cartilage, and ligaments joined tightly to form a strong, flexible framework for the body
tendons
connect muscle to bone and are the most important structure in stabilizing a joint
tendon
connective tissue cords or sheets that attach skeletal muscles to bones o Aponeurosis - tendon that is a broad sheet
Epimysium
connective tissue layer surrounding the muscle as a whole
perimysium
connective tissue sheath surrounding a fascicle
Joint (articular) capsule
connective tissue that encloses the joint cavity o Consists of an outer fibrous capsule that encloses the whole joint o and an inner synovial membrane that secretes the synovial fluid
stem cells
continually divide to produce new keratinocytes
Flexion
decreases the joint angle on the sagittal plane (usually involves bending the joint forward if it can move that way)
muscle tissue
description: Tissue composed of elongated, excitable cells function: Specialized for contraction and movement ex: Skeletal muscles, heart, walls of hollow organs and blood vessels
nervous tissue
description: Tissue containing excitable cells that can also generate a signal function: Specialized for rapid transmission of information to other cells ex: Brain, spinal cord, nerves
connective tissue
description: Tissue with more matrix than cell volume function: Usually specialized to support, bind, or protect organs. Blood is used for transport ex:Tendons, ligaments, cartilage, bone, fat, blood
epithelial tissue
description:Composed of layers of closely spaced cells function:Covers organ surfaces, forms glands, serves for protection, secretion and absorption ex:Epidermis, lining hollow organs, glands
Four tissue classes
epithelial, connective, nervous and muscular
Hyperextension
extends a joint beyond anatomical position
yellow bone marrow
fatty substance that fills long bones in adults
periosteum
fibrous connective tissue sheath covering the external surface of a bone
Fascia
fibrous sheets that separate adjacent muscles from each other
inversion
foot movement that tilts the soles medially toward each other
ossification
formation of bone
secretion
gland's product if it is useful
First gap phase (G1)
he interval between cell division and DNA replication
Articular cartilages:
hyaline cartilage that covers the facing bone surfaces
compact (dense) bone
is solidly filled with opaque matrix. Is always found on the surface of a bone Organized into osteons (cylindrical units of bone structure) Layers of matrix called lamellae arranged concentrically around a central canal, which contains blood vessels and nerves
Hair matrix
just above the dermal papilla, is the exclusive site of cellular mitosis and hair growth
Stratum spinosum
many layers of keratinocytes and some dendritic cells; these keratinocytes stop dividing and start synthesizing keratin
Epiphyseal lines
mark former growth zones from childhood
osteocytes
mature bone cells (former osteoblasts) that have become trapped in the matrix they deposited
Dorsiflexion
movement in which the toes are raised
abductions
movement of a body part away from the midline
Opposition
movement of the thumb to approach the fingertips
plantar flexion
movement that points the toes downward
adduction
movement toward the midline, returning to zero position
matrix
non-living extracellular material
merocrine sweat glands
numerous, and especially abundant on palms, soles and forehead ducts lead to skin surface; produce watery perspiration that serves to cool the body;Sweat has a pH ranging from 4-6
red bone marrow
o Produces red blood cells and platelets o fills all bones in children, fills spongy bone in adults
apocrine sweat gland
o ducts lead onto hair follicles o secretion contains more fatty acids than merocrine sweat glands o especially respond to stress and sexual stimulation o produce pheromones (chemicals that influence the physiology or behavior in other members of the species)
cerumionous glands
o found only in the auditory canal o secretion combines with sebum and dead epidermal cells to form cerumen (ear wax) o ducts lead to the skin surface o cerumen keeps eardrum pliable, waterproofs the auditory canal and has a bactericidal effect
osteoblasts
o function to synthesize and deposit matrix o develop from osteogenic cells, lie on the bone surface
osteoclasts
o large, multinucleated, bone-dissolving cells o lie on the bone surface
sebaceous glands
o produce an oily secretion (sebum) o short ducts open into a hair follicle o Sebum keeps the skin and hair from becoming dry, brittle and cracked
Osteogenic cells
o stem cells that occur on the bone surface o they are the only cells capable of dividing and making more bone cells
Circumduction
one end of the appendage remains mostly stationary while the other makes a circular movement
motor unit
one motor neuron and all the muscle fibers supplied by it small motor units supply a small number of muscle fibers, are easily stimulated to excite them and are involved in weak muscle contractions large motor units supply larger numbers of muscle fibers, require a stronger stimulus to excite them and are involved in stronger muscle contractions
Sarcolemma
plasma membrane of a muscle cell
Retraction
posterior movement
serous gland
produce a thin, watery fluid (like sweat, milk, tears)
melanocytes
produce the dark pigment melanin, which protects the deeper tissues from UV rays in the sunlight
Intramembranous Ossification
produces flat bones of skull a. Begins with a sheet of mesenchyme (embryonic connective tissue) b. Osteoblasts deposit immature bone matrix ("osteoid"), which then hardens c. Osteoblasts trapped in the matrix become osteocytes d. Spaces where there isn't bone fills with blood vessels and red marrow
Endochondral Ossification
produces most of the bones in the body a. Begins with hyaline cartilage b. Formation of primary ossification center (in the diaphysis), bony collar and periosteum c. Vascular invasion, formation of the primary marrow cavity d. Appearance of the secondary ossification center e. Secondary ossification center develops in the epiphyses f. Vascular invasion, formation of the secondary marrow cavity g. Epiphyseal plates close
elevation
raises a body part vertically
Parathyroid hormone (PTH)
raises blood calcium by stimulating bone resorption by osteoclasts
Calcitriol (Vitamin D)
raises blood calcium by stimulating osteoclasts and promoting calcium absorption from food
Sphincter muscles
ring-shaped muscles that control the diameter of an opening
supination
rotation of the forearm so that the palm faces forward or upward
pronation
rotation of the forearm so that the palm faces toward the rear or downward
mucous gland
secrete a protein that absorbs water and becomes mucus (secreted on the respiratory and digestive tracts)
tactile cells
sensory cells for the sense of touch
atrophy
shrinkage of a tissue through a loss in cell size or number, due to lack of use or aging
synovial fluid
slippery lubricant that fills the joint cavity
bone marrow
soft bloody or fatty material enclosed in bones
extension
straightens a joint and returns the body part to anatomical ("zero") position
what type of cells protect the body from abrasion?
stratified squamous cells; linked by desmosomes
functions of skeleton
support; protection; movement; blood formation; storage
cuticle
surface of the hair
pallor
temporary pale or ashen color, results when there is little cutaneous blood flow and skin color is dominated by white dermal collagen o can result from emotional stress, circulatory shock, cold temperatures, or severe anemia
reticular layer
the bulk of the dermis, zone of dense irregular CT. Is very tough (think of the leather of animal hides, which is made from this layer)
differentiation
the development of specialized tissue from stem cells
Cytokinesis:
the division of the cytoplasm
Shaft/diaphysis
the elongated midsection of long bones, provides leverage
Head/epiphysis
the expanded end of a long bone. Functions to strengthen a joint and provide added surface area for a tendons and ligaments
osseous tissue
the hard, calcified tissue of a bone Osseous tissue consists of cells and matrix. Like other connective tissues, the matrix is made of fibers and ground substance
Medullary cavity
the hollow space(s) inside of a bone, filled with marrow
Second gap phase (G2)
the interval between DNA replication and cell division
Prime mover (agonist)
the muscle that produces most of the force during a particular joint action
motor neurons
the nerve cells that stimulate skeletal muscles at the distal end, the axon (also called a nerve fiber) branches to multiple muscle fibers, but each muscle fiber receives only one nerve fiber
depression
the opposite of elevation
Synthesis phase (s)
the period in which a cell replicates its DNA The DNA is unzipped and the nitrogen bases are exposed DNA polymerase (an enzyme) assembles complementary nucleotides for each strand
Mitotic phase (M)
the period in which a cell replicates its nucleus and divides its DNA into two identical sets Prophase, Metaphase, Anaphase, Telophase
synapse
the point where the end of a nerve fiber meets another cell
Excitation
the process of converting an electrical nerve signal to an electrical signal in the muscle fiber
hemoglobin
the red pigment of blood imparts a reddish or pink hue to the skin as blood vessels show through the dermal collagen
fibrosis
the replacement of damaged tissue with scar tissue (collagen) The tissue is held together but does not have its normal function
regeneration
the replacement of dead or damaged cells by the same type of cells as before, thus restoring the normal function Many epithelial tissues are excellent at this (especially the skin and liver)
Sarcoplasmic reticulum (SR)
the smooth endoplasmic reticulum of a muscle fiber It's web wraps around each myofibril It functions as a reservoir for calcium ions When the muscle fiber is stimulated, the SR releases calcium ions into the cytosol to activate the contraction process
Contraction
the step in which the muscle fiber develops tension and may shorten
histology
the study of tissues
Reposition
the thumb's movement back to zero position
Dermal papillae
the upward waves of connective tissue that interlock with the epidermis o this reduces slippage of the epidermis across the dermis, and also produces fingerprints
Articular cartilage
thin layer of hyaline cartilage that covers the ends of bones in a joint
endosteum
thin layer of reticular connective tissue lining that separates the marrow from the bone
Papillary layer
thin zone of areolar connective tissue (CT) beneath the epidermis, filling the dermal papillae
stratum lucidum
this is only present in the thick epidermis of the palms and soles. It is a thin, clear layer of dead cells
eversion
tilts the soles away from each other
synaptic cleft
tiny gap between the nerve fiber and the muscle fiber
hyperplasia
tissue growth though cell multiplication
Transverse (T) tubules
tunnel like infoldings of the plasma membrane Functions to carry an electrical current from the surface of the cell to the interior of the cell
Stratum corneum
up to 30 layers of dead, keratin-packed keratinocytes. The dead cells exfoliate (flake off) from the surface
excretion
waste product of a gland
neuromuscular junction (NMJ)
when a nerve fiber meets a muscle cell
Relaxation
when a nerve stops stimulating the muscle cell, the muscle cell relaxes and returns to its resting length.
carotene
yellow pigment acquired from foods, can become concentrated in the stratum corneum and hypodermis
spongy bone
a porous lattice filled with blood-filled spaces. Is always found in the interior of a bone
flat bones
Act as protective plates covering delicate organs (sternum and skull) or as a broad attachment point for muscles (scapula) Consist of two layers of compact bone enclosing a middle layer of spongy bone
dermis
Consists of fibrous connective tissue, is mostly collagen Well supplied with blood vessels, sweat glands, sebaceous (oil) glands, and nerve endings
Functions of Muscles
Movement Stability of joints Control of body openings and passages Heat generation Glycemic control (regulation of blood glucose) - skeletal muscles play a significant role in stabilizing blood glucose levels by absorbing a large share of it
Cartilaginous joints
Other name: amphiarthrosis Structure: adjacent bones are bound by cartilage Mobility: varies, but can be a little movement Examples: o pubic symphysis (where fibrocartilage joins the right and left bones together) o intervertebral discs (fibrocartilage joins consecutive vertebrae to each other)
Synovial joints
Other name: diarthrosis Overall structure: adjacent bone surfaces are covered in hyaline cartilage and surrounded by a joint cavity that is filled with fluid Mobility: most are highly mobile Examples: o knee joint, elbow, finger joints, hip, shoulder, jaw and most other joints in the body
Fibrous joints
Other name: synarthrosis Structure: adjacent bones are bound by collagen fibers Mobility: most have very little Examples: o skull sutures o joint between the radius and ulna (the interosseus membrane) o joint between the tibia and fibula
The Hip (JOINT)
Structure: the head of the femur inserts into the acetabulum of the hip socket Other features: the acetabular labrum is a ring of fibrocartilage around the rim of the acetabulum, which deepens the socket Stabilization comes from three ligaments (iliofemoral, pubofemoral, ischiofemoral)
The shoulder (JOINT)
Structure: the head of the humerus inserts into a shallow glenoid cavity of the scapula Other features: the glenoid labrum is a ring of fibrocartilage around the rim of the glenoid cavity, which deepens the socket Stabilization comes from o primarily from the tendon of the biceps brachii muscle o rotator cuff: tendons of four scapular muscles (arise from the scapula) reinforce the joint capsule
The jaw (temperomandibular joint, TMJ) (JOINT)
Structure: the mandibular condyle of the mandible inserts into the mandibular fossa of the temporal bone
dystrophin
dystrophin is a protein that connects myofilaments to the sarcolemma and extracellular matrix If dystrophin does not function correctly, the sarcolemma will tear and the muscle tissue will eventually be scarred. With time, the muscle is replaced with adipose and scar tissue, resulting in paralysis. (This is occurs in Muscular Dystrophy)
serous membrane (serosa)
line the thoracic and abdominal cavities, cover the external surfaces of organs composed of a simple squamous epithelium produce a thin, watery fluid
mucous membranes
line tracts of the body that open to the exterior environment (digestive, respiratory, urinary and reproductive tracts) are covered by mucus that traps bacteria and foreign particles
hypodermis
looser CT and adipose tissue binds the skin to underlying muscles subcutaneous fat pads the body, serves as a energy reservoir, provides thermal insulation
necrosis
pathological death of tissue due to trauma, toxins, infection, etc. Often spreads
apoptosis
programmed cell death, the normal death of cells that have completed their function. This is caused by lysosomes that degrade the cell's DNA and proteins does not spread from cell to cell
exocrine gland
release a secretion onto an epithelial surface release a secretion through a duct Examples: sweat glands, salivary glands, mammary glands, liver Further classified by the type of secretion
endocrine glands
release their products into the bloodstream, do not have ducts the secretion is a hormone, which serves as a chemical signal to other organs Examples: pituitary gland, thyroid gland, adrenal glands
why can few infections organisms penetrate the skin?
skin cells are packed with a tough protein (keratin) skin is dry skin is covered with an acidic film
hair receptors
(nerve fibers) coil around the follicle and respond to hair movements
keratinocytes
cells packed with keratin
dendritic cells
cells that alert the immune system to foreign invaders
medulla
centeal core that's only present in thick hairs (i.e.: eyebrows and lashes)
tendons
collagen bands that attach muscle to bone
Stratum granulosum
3-5 layers of keratinocytes with dark-staining granules. Keratin filaments clump together and form a water-proofed layer. The cells die here as a result.
ligaments
collagen bands that hold bones together at the joints
thermoregulation
The skin stabilizes body temperature by regulating heat exchange with the environment o blood flow near the skin is reduced to retain heat o blood flow near the skin is increased to prevent overheating
Dermal papilla
a bit of vascular CT that grows into the bulb and provides the hair with its sole source of nutrition
Hematoma
a bruise, a mass of clotted blood showing through the skin o can result from trauma, platelet deficiencies, anticoagulant drugs, or hemophilia
Fascicle -
a bundle of muscle fibers
gland
a cell or organ that releases substances for use elsewhere in the body or for elimination from the body
Mineral deposition
a crystallization process in which osteoblasts extract calcium and phosphate from the blood and deposit it in the osseous tissue
hair follicle
a diagonal tube of epithelium and connective tissue that penetrates the dermis
bursa
a fibrous sac filled with synovial fluid, acts to cushion muscles or help tendons slide more easily over the joints
tissue
a group of similar cells and cell products that work together to perform a specific function
albinism
a hereditary lack of pigmentation in the skin, hair and eyes due to an inability to synthesize melanin
epidermis
a keratinized stratified squamous epithelium composed of keratinocytes, dendritic, melanocytes, tactile, and stem cells
Synergista muscle
a muscle that aids the prime mover. The synergist may stabilize a joint, restrict unwanted movements, or modify the direction of the movement so that the action of the primary mover is more coordinated and specific
anatagonist
a muscle that opposes the prime mover
Fixator
a muscle that restricts a bone from moving, holding it steady so that another muscle attached to it can pull on something else
Joint (articular) cavity
a narrow space separating the two bones
Articular cartilage/disc
a pad that crosses the entire joint
meniscus
a pad that doesn't cross the entire joint
resorption
a process in which the osteoclasts dissolve bone, releasing the minerals into the blood and making them available for other uses
stratum basale
a single layer of stem cells, keratinocytes, melanocytes and tactile cells
hair
a slender filament of keratinized cells that grows from a hair follicle Hair is made from a harder keratin than what's in the skin
Piloerector muscles
a small smooth muscle attached the hair follicle. When it contracts, pulls the follicle into a vertical position
Endomysium -
a thin sleeve of loose connective tissue that encloses a single muscle cell (which is also called a muscle fiber) o As an insulator, it prevents electrical activity in one muscle cell from directly stimulating adjacent fibers
jaundice
a yellowing of the skin and whites of the eyes o occurs in various liver diseases (cancer, hepatitis, cirrhosis and some blood diseases with a rapid rate of erythrocyte breakdown)
Erythema
abnormal redness of the skin (as in sunburn, exercise, hot weather, embarrassment)
Protraction
anterior movement on a horizontal plane
cortex
beneath the cuticle, makes the bulk of hair
Cyanosis
blueness of the skin resulting from oxygen deficiency in the blood or reduced dermal blood flow in cold weather
axon terminal
bulbous swelling at the end of a nerve fiber/axon
Myofibrils
bundles of contractile proteins Myofilaments - parallel protein filaments that make up a myofibril Thick filaments are made of the protein myosin Thin filaments are made of the protein actin o A thin filament also has two proteins (troponin and tropomyosin) that act together as a molecule switch that either allows or prohibits muscle contraction
