| Term | Definition |
| skin layers | epidermis (superficial layer)
dermis
NOT TECHNICALLY A LAYER:
Hypodermis or superficial fascia |
| epidermis | top layer of skin
made of keratinized stratified squamous epithelium
4-5 layers
4 cell types
keratinocytes, melanocytes, merkel cells, and langerhan's cells,
function: protection |
| cell types in epidermis | keratinocytes:
melanocytes:
Merkel Cells:
Langerhans cells: |
| keratinocytes: | mostly produce keratin (fibrous protein) |
| melanocytes | produce melanin and makes up 10-25% of the cells in the lower epidermis |
| Merkel Cells | touch receptors (tactile) |
| Langerhans cells | macrophages that assist in cell immunity |
| layers of the epidermis | top to bottom:
stratum corneum
stratum granulosum
stratum spinosum
stratum basale |
| stratum corneum | 20-30 rows of keratinized dead cells
3/4 of the thickness of the epidermis
function:
protection from abrasion, waterproofs, barrier against attack |
| Stratum Granulosum | 3-5 layers of layers that get flattened
Keratohyaline and lamellated granules accumulate |
| Stratum Lucidum (clear layer)
ONLY FEET AND HANDS | thick skin only (soles of feet and palms of hands)
several layers of DEAD keratinized cells |
| Stratum Spinosum | Abundant melanin granules in keratinocytes
dendritic or Langerhan’s cells |
| Stratum Basale | attached to the dermis
one row of stem cells
it takes 25-45 days for cells to go from basal layer to top of skin |
| dermis | strong and flexible connective tissue
two layers:
reticular & papillary |
| papillary layer | areolar connective tissue with collagen and elastic fibers
Dermal papillae contain:
Capillary loops
Meissner’s corpuscles
Free nerve endings |
| Reticular layer | 80% thickness of the dermis
contain collagen fibers and elastic fibers |
| skin markings | friction ridges and cleavage lines |
| friction ridges | Epidermal ridges that are on top of l deeper dermal papillary ridges (form friction ridges of fingerprints) |
| cleavage lines | Collagen fibers arranged in bundles form cleavage (tension) lines |
| Incisions made parallel to cleavage lines heal more readily | true |
| Sensory receptors in dermis | Pacinian corpuscles
Meissner corpuscles
free nerve endings |
| Pacinian corpuscles | stimulated by heavy pressure deep in dermis |
| Meissner corpuscles | tactile sense to light touch (dermal papillae) |
| Free Nerve endings | respond to temperature (in basal layer of epidermis) |
| Hypodermis | subcutaneous layer below skin
composed of adipose tissue and areolar connective tissue |
| Skin color pigments | Melanin
Carotene
Hemoglobin |
| Melanin | Produced in melanocytes; migrates to keratinocytes where it forms “pigment shields” for nuclei
Freckles and pigmented moles:
Local accumulations of melanin |
| Carotene | Yellow to orange, most obvious in the palms and soles |
| Hemoglobin | Responsible for the pinkish hue of skin |
| Appendages of the skin | Sweat glands
Oil glands
Hairs and hair follicles
Nails |
| Sweat gland types | Eccrine
Apocrine |
| Eccrine sweat glands | Abundant on palms, soles, forehead and all over the body
Sweat: 99% water, NaCl, vitamin C, antibodies, metabolic wastes
Ducts connect to pores
Function in thermoregulation |
| Apocrine sweat glands | Confined to axillary and anogenital areas
Sweat: fatty substances and proteins
Ducts connect to hair follicles
puberty onward (as sexual scent glands?)
Does not participate in thermoregulation |
| Specialized apocrine glands | Ceruminous glands—in external ear canal; secrete cerumen
Mammary glands |
| Sebaceous (oil) glands | Widely distributed
Most develop from hair follicles
Become active at puberty |
| Sebum | Oily holocrine secretion
Bactericidal
Softens hair and skin |
| Functions of hair | Maintain warmth
Alerting the body to presence of insects on the skin
Guards scalp against physical trauma, heat loss, and sunlight |
| Hair distribution | over the entire body except for palms, soles, and lips |
| Hair Follicle parts | shaft
hair root
bulb |
| hair follicle wall | 2 layers
outer connective tissue root sheath
inner epithelial root sheath |
| hair follicle location | from epidermal surface to dermis |
| Arrector pilli | smooth muscle attached to follicle
causes goose bumps |
| Hair follicle receptor (root hair plexus) | Sensory nerve endings around each hair bulb
Stimulated by bending a hair |
| Types of hair | Vellus
Terminal |
| Vellus | pale, fine body hair of children and adult females |
| Terminal | coarse, long hair of eyebrows, scalp, axillary, and pubic regions (and face and neck of males) |
| Functions of Integumentary System | Protection (3 types)
Body temp regulation
cutaneous sensations
metabolic function
blood reservoir
excretion |
| Function: Protection | Three types:
Chemical
Physical/mechanical barriers
Biological barriers |
| Protection: chemical barrier | Low pH secretions (acid mantle) and defensins retard bacterial activity |
| Protection: physical barrier | Keratin and glycolipids block most water and water- soluble substances |
| Protection: biological barrier | Dendritic cells, macrophages, and DNA |
| Function: Body Temp | ~500 ml/day of routine insensible perspiration (at normal body temp)
At high temps, dilation of dermal vessels and increased sweat gland activity (sensible perspirations) cool the body |
| Function: Cutaneous sensations | Temperature, touch, and pain |
| Function: Metabolic functions | Synthesis of vitamin D precursor and collagenase |
| Function: blood reservoir | up to 5% of body’s blood volume |
| Function: excretion | nitrogenous wastes and salt in sweat |
| Skin cancer types | Basal cell carcinoma (least malignant, most common)
Squamous cell carcinoma (second most common)
Melanoma (most dangerous) |
| Basal cell carcinoma | Stratum basale cells proliferate and slowly invade dermis and hypodermis
Cured by surgical excision in 99% of cases |
| Squamous cell carcinoma | Involves keratinocytes of stratum spinosum
Most common on scalp, ears, lower lip, and hands
Good prognosis if treated by radiation therapy or removed surgically |
| Melanoma | Involves melanocytes
Highly metastatic and resistant to chemotherapy
Treated by wide surgical excision accompanied by immunotherapy |
| Burns | damage: tissue damage, denatured protein, cell death)
Immediate threat: Dehydration and electrolyte imbalance, leading to renal shutdown and circulatory shock |
| Rule of Nines | Used to estimate the volume of fluid loss from burns
head and neck: 9%
upper limbs: 18%
trunk: 36%
lower limbs: 36%
perineum: 1% |
| Partial Thickness Burns | First degree
Second degree |
| First Degree burn | Epidermal damage only
Localized redness, edema (swelling), and pain |
| Second degree burn | Epidermal and upper dermal damage
Blisters appear |
| Full Thickness Burn (3rd degree) | Entire thickness of skin damaged
Gray-white, cherry red, or black
No initial edema or pain (nerve endings destroyed)
Skin grafting usually necessary |
| skeletal cartilage | Has no blood vessels
3 types:
hyaline
fibrocartilage
elastic |
| types of bone growth | oppositional
interstitial |
| interstitial growth | bones to grow in length |
| oppositional growth | bones grow in thickness (width) |
| axial skeleton | bones of the skull, vertebral column, and rib cage |
| appendicular skeleton | bones of the upper and lower limbs, shoulder, and hip |
| long bones | longer than they are wide (humerus, tibia, etc) |
| short bones | Cube-shaped bones (in wrist and ankle)
Sesamoid bones (within tendons, e.g., patella) |
| Flat bones | Thin, flat, slightly curved |
| irregular bones | Complicated shapes |
| Functions of bones | Support –
Protection –
Movement –
Mineral storage –
Blood cell formation
Triglyceride |
| Function: Support | form the framework that supports the body and cradles soft organs |
| Function: Protection | provide a protective case for the brain, spinal cord, and vital organs |
| Function: Movement | provide levers for muscles |
| Function: Mineral storage | reservoir for minerals, especially calcium and phosphorus |
| Function: Blood cell formation | hematopoiesis occurs within the marrow cavities of bones |
| Function: Energy storage | Triglyceride (energy) storage in bone cavities |
| Bone textures | Compact bone
Spongy bone |
| Compact bone | Dense outer layer
Made of osteons |
| Spongy (cancellous) bone | Made of honeycomb of trabeculae |
| Structure of a long bone | Diaphasis
Medullary Cavity
Epiphysis |
| Diaphasis | shaft of bone
Compact bone collar surrounds medullary (marrow) cavity |
| Medullary Cavity | in adults contains fat (yellow marrow) |
| Epiphyses | Expanded ends
Spongy bone interior
Epiphyseal line (remnant of growth plate)
Articular (hyaline) cartilage on joint surfaces |
| Membranes of bones | Peristeum
Endosteum |
| Endosteum | Delicate membrane on internal surfaces of bone
Also contains osteoblasts and osteoclasts |
| Peristeum | Outer: fibrous layer
Inner: osteogenic layer
Osteoblasts
Osteoclasts
Osteogenic cells (stem cells)
Nerve fibers, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foramina
Secured to underlying bone by Sharpey’s fibers |
| diploe | spongy bone in flat bones |
| Structure of Short, Irregular, and Flat Bones | Periosteum-covered compact bone on the outside
Endosteum-covered spongy bone within
Bone marrow between the trabeculae
Have no diaphysis or epiphyses |
| Location of Hematopoietic Tissue (Red Marrow) | Adults: red marrow cavities
Trabecular cavities of the heads of the femur and humerus
Trabecular cavities of the diploë of flat bones
Infants: red marrow
Medullary cavities
All spaces in spongy bone |
| Osteoblasts | bone forming cells |
| Osteoclasts | break down bone |
| Osteocytes | mature bone cells |
| Osteogenic (osteoprogenitor) cells | Stem cells in periosteum and endosteum that give rise to osteoblasts |
| Haversian system, or osteon | structural unit of compact bone |
| Lamellae | Weight-bearing
Column-like matrix tubes |
| Chondrocytes | Are in between the lamella |
| Lacunae | small cavities that contain osteocytes |
| types of canals in compact bone | Perforating (Volkmann’s) canals
Central (Haversian) canal
Canaliculi |
| Perforating (Volkmann’s) canals | At right angles to the central canal
Connects blood vessels and nerves of the periosteum and central canal |
| Central (Haversian) canal | Contains blood vessels and nerves |
| Canaliculi | hairlike canals that connect lacunae to each other and the central canal |
| Trabeculae | spongy bone
align along lines of stress
no osteons
capillaries in endosteum supply nutrients
Contain irregularly arranged lamellae, osteocytes, and canaliculi |
| Chemical Composition of Bone: Organic | osteoblasts
osteoclasts,
osteocytes,
osteogenic cells,
osteoid |
| Osteoid | organic bone matrix secreted by osteoblasts
Ground substance (proteoglycans, glycoproteins)
Collagen fibers
Provide tensile strength and flexibility |
| Chemical Composition of Bone: Inorganic | Hydroxyapatites (mineral salts) |
| Hydroxyapatites (mineral salts) | 65% of bone by mass
Mainly calcium phosphate crystals
Responsible for hardness and resistance to compression |
| Osteogenesis | bone tissue formation |
| Stages of osteogenesis | Bone formation—begins in the 2nd month of development
Postnatal bone growth—until early adulthood
Bone remodeling and repair—lifelong |
| Types of Ossification | Intramembranous ossification
Endochondral ossification |
| Intramembranous ossification | Membrane bone develops from fibrous membrane
Forms flat bones, e.g. clavicles and cranial bones |
| Endochondral ossification | Cartilage (endochondral) bone forms by replacing hyaline cartilage
Forms most of the rest of the skeleton
Uses hyaline cartilage models
Requires breakdown of hyaline cartilage prior to ossification |
| postnatal bone growth | interstitial
oppositional |
| Growth in length of long bones | 4 zones:
Proliferation (growth)
Hypertrophic
Calcification
Ossification (osteogenic) |
| Growth Hormone | stimulates epiphyseal plate activity |
| Thyroid Hormone | modulates activity of growth hormone |
| Testosterone and estrogens (at puberty) | Promote adolescent growth spurts
End growth by inducing epiphyseal plate closure |
| Bone Deposit | occurs where a bone is damaged which provides extra support
person needs to have a healthy diet |
| Bone Reabsorption | osteoclasts secrete
Lysosomal enzymes (digest organic matrix)
Acids (convert calcium salts into soluble forms) |
| Hormones in bone
(BONE GROWTH) | children: growth and thyroid hormone
adults: estrogen or testosterone |
| Hormones for calcium homeostasis | when blood Ca is low: PTH
increases activity of osteoclasts
When blood calcium is high: Calcitonin
increases activity of osteoblasts |
| Osteoporosis | loss of bone mass
osteoclasts outpace osteoblasts |
| Osteomalacia | calcium salts not deposited which causes vitamin d deficiency |
| Rickets | childhood disease that causes bowed legs |
| Wolff's law | A bone grows or remodels in response to forces or demands placed upon
ex. if right handed: bones of right hand are stronger than the left hand
area where bone curves is thickest |
| Why is calcium necessary? | Transmission of nerve impulses
Muscle contraction
Blood coagulation
Secretion by glands and nerve cells
Cell division |
| cranial bones | frontal, pariteal, occipital, temporal, sphenoid, ethmoid |
| temporal bones projections | Zygomatic process
Mastoid process
Styloid process |
| temporal bones openings | External auditory/acoustic meatus where ear is
Jugular foramen
Carotid canal |
| mandibular fossa | Mandibular fossa –
- Articulation: mandibular fossa articulates with the mandibular condyle of the mandible |
| occipital bone | contains:
foramen magnum: for spinal cord
occipital condyles
external occipital protruberance
hypoglossal canal |
| Sphenoid bone | Optic canal/foramen – between the 2 wings
R - foramen rotundum
O – foramen ovale
S – foramen spinosum |
| Ethmoid bone | upper part of nasal septum – vertical plate |
| Sutures | joints between cranial bones |
| Corona suture | between frontal and parietal |
| sagittal suture | between parietal bones |
| Squamous suture | between temporal and parietal |
| lambdoid suture | between occipital and parie |
| Facial bones | Mandible
Maxillae
Palatine
Zygomatic
Nasal
Lacrimal
Vomer
Inferior nasal concha |
| Mandible | lower jaw
body
ramus
mandibular condyles – posterior projection of the ramus
articulation: mandibular condyle articulates with mandibular fossa of the temporal bones
coronoid process – anterior projection of the ram |
| nasal bone | forms the bridge of the nose |
| lacrimal bone | has a depression of the nasolacrimal duct |
| vomer | has a depression of the nasolacrimal duct |
| inferior concha | plates of bone in the nasal cavity |
| zygomatic bone | cheek bone
forms the zygomatic arch with the zygomatic process of the temporal bone |
| hard palate | anteriorly – maxilla
posteriorly – palatine bone |
| nasal septum | superior part – ethmoid bone
inferior part – septal cartilage |
| fetal skull | Fontanels – spaces between cranial bones
anterior fontanel – closes after 11/2 years
posterior fontanel – closes at birth |
| Paranasal sinuses | Paranasal sinuses: mucus membrane lined air filled cavities of the bones
maxillary sinus
frontal sinus
ethmoid sinus
sphenoid sinus |
| Parts of the vertebal column | Cervical vertebrae – 7
Thoracic vertebrae – 12
Lumbar vertebrae – 5
Sacrum -1
Coccyx – 1 |
| vertebral curvatures | Cervical and lumbar
Thoracic and sacral |
| scoliosis | abnormal lateral curvature |
| kyphosis | exaggerated thoracic curvature (hunchback) |
| Lordosis | exaggerated lumbar curvature |
| Intervertebral discs | between the vertebrae, made with fibrocartilage |
| Intervertebral foramen/mina | holes between the vertebra laterally. The spinal nerves emerge from it/them |
| cervical vertebrae | Special features of all cervical vertebrae:
transverse foramen – on all cervical vertebrae
Spinous process - bifid or divided and short – except C1, and C7
Small vertebrae |
| atlas: C1 | No body
No spinous process
Transverse foramen present
Superior articular process – large
Articulation: superior articular process articulates with the occipital condyle of the skull |
| Axis: C2 | body
transverse foramen present |
| C3-C7 | Body small
Spinous process bifid except C7
Transverse foramen
C7 – vertebra prominence - spinous process is long – looks like in thoracic vertebrae |
| Lumbar vertebrae (5) | large vertebrae
spinous process – short and thick, like a hatchet |
| Sacrum | forms posterior wall of the pelvis
sacral foramina
ala – laterally
articulation: ala articulates with the auricular surfaces of hip bone (illium) |
| Coccyx | tail bone |
| Thoracic cage | thoracic vertebra
sternum
ribs and the costal cartilages |
| Sternum | manubrium – superior part
articulation: manubrium articulates with the clavicle and 1st and 2nd ribs
Body
articulation: body articulates with costal cartilages
xiphoid process |
| ribs | all attach posteriorly to vertebrae
all attach anteriorly through costal cartilages to the sternum directly or indirectly |
| ribs 1-7 (true ribs) | Ribs 1-7- true ribs – attach directly to sternum through costal cartilages |
| ribs 8-12 (false ribs) | attach indirectly to sternum by joining costal cartilage of the rib above |
| ribs 11-12 (floating ribs) | no anterior attachment to the sternum |
| Parts of a rib | Head
Articulation: head of the rib articulates with the demi facets on the vertebral body
Neck
Tubercle
Articulation: tubercle of the rib articulates with the facet on transverse process |
| Appendicular | Pectoral girdle
upper limb bones
pelvic girdle
lower limbs |
| Pectoral girdle: | Clavicle and scapula |
| upper limb bones | Arm, forearm, wrist, hand, fingers |
| pelvic girdle | Hip bones (2) |
| lower limbs bones | thigh, leg, ankle, foot, toes |
| clavicle | sternal end
Articulations: Sternal end or medial end articulates with sternum
acromial end
Articulations: Acromial end or lateral end articulates with acromial process of scapula |
| Scapula | boarders superior, lateral and medial
anterior surface:
Corocoid process
Subscapular fossa |
| Humerus | arm bone
Superior end:
Head of humerus –
Articulation – head with the glenoid fossa of the scapula
Neck |
| Humerus: Coronoid fossa | medial, on the anterior surface of humerus, above the trochlear
Articulation: coronoid fossa articulates with the coronoid process of ulna when the elbow is flexed |
| Humerus: Radial fossa | lateral, on the anterior surface of humerus, above the capitulum
articulation: radial fossa articulates with the radial head when the elbow is flexed |
| Humerus: Olecranon fossa | on the posterior surface of humerus
articulation: olecranon fossa articulates with the olecranon process of the ulna when the elbow is extended |
| Carpal bones | 8 |
| Metacarpals | 5 |
| Phalanges | 14
2 in thumb
3 in each digit |
| Pelvic girdle | Hip bones: 3
Ileum (hands of hips)
Ischium (sit on)
Pubic (in the front) |
| true pelvis | below pelvic brim |
| Femur: Distal end: Medial condyle | medially
Articulation: medial condyle articulates with the medical condyle of tibia |
| articulation | site where two bones meet |
| functions of articulations | Give the skeleton mobility
Hold the skeleton together |
| Three functional classifications: | Synarthroses
Amphiarthroses
Diarthroses |
| Diarthroses | freely movable |
| Amphiarthroses | slightly movable |
| Synarthrosis | immovable |
| Three structural classifications | Fibrous
Cartilaginous
Synovial |
| Flexion | bending movement that decreases the angle of the joint |
| extension | reverse of flexion; joint angle is increased |
| abduction | movement away from the midline |
| adduction | movement toward the midline |
| circumduction | movement describes a cone in space |
| plantar flexion | extension of the foot (pointed toes) |
| dorsiflexion | flexion of the foot (flat foot) |
| Inversion | turn sole medially (sole inwards) |
| nonaxial | slipping movements only |
| uniaxial | movement in one plane |
| biaxial | movement in two planes |
| multiaxial | movement in or around all three planes |
| insertion | attachment to the movable bone |
| origin | attachment to the immovable bone |
| intracapsular | deep to capsule; covered by synovial membrane |
