Exam #2 Chapters 5, 6, and 8 Flashcards
Dermis functions
Gives structural strength.
Connective Tissue with many fibers, fibroblasts, macrophages. Some adipocytes and blood vessels.
Contains nerves, blood vessels, hair follicles, smooth muscles, glands, and lymphatic vessels.
sensory functions of dermis
pain, itch, tickle, temperature, touch, pressure, two-point discrimination
how many layers of dermis. name the layers.
2 layers!
papillary layer
reticular layer
papillary layer of dermis
named for dermal papillae
attaches epidermis to dermis
nourishes the epidermis
consists of areolar tissue
contains: capillaries, lymphatic capillaries, sensory neurons
reticular layer of dermis
meshwork of DENSE IRREGULAR CT
COLLAGEN FIBERS (extend into papillary layer and hypodermis)
Structural strength and support
Elastin fibers
Allows for elasticity and stretch
Contains similar structures as papillary layer BUT ALSO SWEAT GLANDS AND HAIR FOLLICLES
Lines of cleavage, describe.
Formed by arrangement of collagen and elastin fibers in skin.
Significant for SURGERY and WOUND HEALING
Parallel to cleavage: better healing and less scarring Perpendicular to cleavage: remain open and more scarring.
Hypodermis
Separates skin from deeper structures.
Stabilizes skin to underlying tissues.
Allows independent movement.
Dominated by adipose tissue
Storage of energy
In men (accumulation): neck, arms, lower back, buttocks
In women: breasts, buttocks, hips, thighs
Both men/women: few cells on back of hands/surfaces of feet, more in abdominal region
Accessory Structures of Integumentary System
Sensory receptors
monitor external environment
Hair and hair follicles
produce hairs that protect skull
produce hairs that provide delicate touch sensations
Exocrine Sweat Glands
assist in thermoregulation
excrete wastes
lubricate epidermis
Nails
protect and support tips of fingers and toes
ACCESSORY STRUCTURES
sensory receptors (of integumentary) function
monitor external environment
ACCESSORY STRUCTURES
Hair and hair follicles (integumentary) function
produce hairs that protect skull
produce hairs that provide delicate touch sensations
ACCESSORY STRUCTURES
Exocrine Sweat glands (integumentary) function
thermoregulation
excrete waste
lubricate epidermis
ACCESSORY STRUCTURES
Nails (integumentary) function
protect and support fingers and toes
Epidermis
what are the skin sensory receptors located here?
Dermis
what are the skin sensory receptors located here?
EPIDERMIS
merkel cells
tactile discs (monitor epidermis)
free nerve endings
DERMIS
more specialized receptors
tactile corpuscles (in dermal papillae)
lamellate corpuscles (in reticular layer)
Merkel cells found in ________ layers of where?
Merkel cells found in DEEP layers of EPIDERMIS.
(skin sensory receptor)
free nerve endings
(epidermis skin sensory receptor)
extensions for pain and temperature
tactile corpuscles
(skin sensory receptor of dermis)
detect light touch
located in dermal papillae
lamellated corpuscles
(skin sensory receptor of dermis)
deep pressure/vibration
located in reticular layer of dermis
“lamellated” or “layers” - structure
protection… protection against what?
(integumentary system)
against UV light, microorganisms, water loss.
what kind of sensations?
(integumentary system?)
sensory receptors for temperature, touch, pressure, pain.
regulation… regulation of what?
(integumentary system)
temperature regulation
production… production of what?
(integumentary system)
vitamin D production
excretion… excretion of what?
(integumentary system)
very SMALL amount of waste product
Body’s first line of defense against environment?
Integument! (or skin)
2 major components of integumentary system are what?
cutaneous membrane
accessory structures
cutaneous membrane layers
epidermis
stratified squamous epithelium
dermis
papillary layer (areolar CT)
reticular layer (dense irregular CT)
*hypodermis - NOT PART OF SKIN, WHY ITS CALLED HYPODERMIS, IT’S BELOW THE DERMIS, OR SKIN. Not a cutaneous membrane. Not part of integument. I repeat, NOT a part of the integument. Separates integument from deep fascia. Helps hold body together. Areolar loose CT and adipose tissue.
Cutaneous plexus is what
network of blood vessels throughout the dermis
epidermis… vascular or avascular
avascular.. nourished by diffusion from CAPILLARIES OF PAPILLARY LAYER of DERMIS. No direct blood supply.
Epidermis is dominated by these epithelial cells
KERATINOCYTES
Epithelial cells are constantly produced in _________. Are shed at __________.
deepest layers, exposed surface.
Another word for “layers”
“strata”
Most of body covered with how many strata?
4 strata (thin skin)
THICK SKIN HAS 5 (stratum lucidum)
Skin is thickest where?
Palms of hands and soles of feet
Dermal papilla function
Increase the surface area between epidermis/dermis. Why? Attachment and diffusion of nutrients to the AVASCULAR epidermis.
Your fingerprints are what?
Your dermal papilla. NO TWO PEOPLE HAVE THE SAME FINGERPRINTS!!! PERIOD. NOT EVEN IDENTICAL TWINS.
Fingerprints and footprints are your thick skin. They are a representation of your _______.
Dermal papilla.
Increase in number of layers in stratum corneum..
callus. when this occurs over a bony prominence, a CORN forms.
What is the protein that makes cells waterproof?
(integumentary system)
keratin! keratinocytes produce keratin for strength. once a cell is keratinized, it can’t do anything. its waterproof, can’t exchange fluid, ions, waste… it dies.
Epidermal cell type that is part of the immune system
langerhans cells, phagocytic cells that patrol epidermis for pathogen entry.
COME LET’S GRAB SOME BEER!!! (mnemonic)
Corneum, lucidum, granulosum, spinosum, basale
Stratum corneum (means horn)
outermost layer
15-30 layers - keratinized cells filled with keratin
dead cells still attached to desmosomes
stay in stratum corneum - 2 weeks before shed
stratum lucidum (means clear)
absent in thin skin
separates corneum layer from underlying layers
flattened dead cells filled with keratin AND KERATOHYALIN
Stratum granulosum
3-5 layers keratinocytes
living cells stopped dividing, started making keratin and keratohyalin
protein fibers develop, membranes become less permeable
Stratum spinosum
8-10 layers of live keratinocytes bound by desmosomes. In microscope slides, CELLS LOOK SPINY.
Where dendritic cells (immune system cells) ARE FOUND. Defends against pathogens/SUPERFICIAL CANCERS
Stratum basale
actively DIVIDE.
Merkel cells found here.
Dandruff is what layer of strata being shed from the outer layers of skin of the scalp?
stratum corneum
A splinter in the top of the hand penetrates the third layer of skin…. what layer has it penetrated???
SPINOSUM!!! Question says, “top of hand” not “palm of hand” - therefore there are only 4 layers in the top of the hand. No stratum lucidum (palm of hand or sole of foot would have 5 layers).
Presence of pigments of skin are influenced by
melanin and carotene
palms are thick with keratin but have LESS melanin, that’s why…
someone who has dark skin has lighter colored palms as opposed to rest of body…
melanin is manufactured from
amino acid TYROSINE.
Melanocytes are only found in the stratum
BASALE
Melanocytes package up the melanin in a vesicle called a _______, and releases it by ___________.
Keratinocytes take up the ________ by _________.
melanosome, exocytosis.
melanin, ENDOCYTOSIS.
Sunlight damages collagen. Melanin is natural sunscreen. Dark skinned people have more natural sunscreen. That’s why…
Morgan Freeman still looks great at 118 years old…
Melanin uptake and storage by keratinocytes
The melanosome is digested via endocytosis and releases melanin. The melanin do something special, they surround the nuclei of your KERATINOCYTES and shield the nucleus from UV radiation with your melanin, nature’s SPF.
Hair on body found EXCEPT
palms of hands/toes, lips, external genitalia
how many hairs on body
2.5 million (about)
what percentage of hair is on body (not head)
75%
Two types of hair, describe them
- terminal hairs: large coarse, darkly pigmented hairs such as on head, armpits, groin
- vellus hairs (smaller, shorter, delicate on general body surface
A hair follicle is composed of what tissues
epithelial tissue and connective tissue
difference between hair shaft and hair root
hair shaft is the exposed part of the hair to the environment, but it DOES extend beneath the skin. the hair root is the ANCHORING portions where growth occurs.
what is a root hair plexus
a root hair plexus is a network of sensory nerves that surround the BASE of the hair follicle.
talk about the arrector pili muscle
it is a smooth muscle that pulls on the follicle causing the hair to stand erect. Responsible for “goosebumps”
Internal root sheath
(layers of the hair follicle)
surrounds hair root; deepest layer, superficial to cuticle
External root sheath
(layers of hair follicle)
runs the entire length of the follicle
Glassy membrane
(layers of the hair follicle)
thick, clear, basal lamina
connective tissue sheath
(layers of the follicle)
outermost layer
Base of hair follicle is called ____ and has _____?
base has HAIR BULB (epithelial cap) and HAIR PAPILLA (peg of connective tissue with blood vessels and nerves)
layers of the hair shaft
cuticle (outermost layer made of KERATIN)
cortex (middle layer with HARD KERATIN for stiffness)
medulla (core with flexible SOFT KERATIN)
Talk about the “active phase” and “resting phase” of hair growth
ACTIVE PHASE
hair grows 2-5 years at .33mm per day
variation in growth rate/cycle duration varies from person to person
RESTING PHASE
follicle regresses and enters
hair loses attachment tothefollicleand becomes_a CLUB HAIR
CLUB HAIR is shed as follicle reactivates - replacement hair growth begins
What is responsible for hair color?
differences in structure and variation in pigments produced in melanocytes at hair papilla
*different forms of melanin for different hair colors
Pigments produced in melanocytes __________ with age.
DECREASES!
White hair lacks pigment and has air bubbles in medulla.
Sebaceous glands, aka_______. Talk about them.
They are OIL GLANDS.
More specifically, the are holocrine glands that discharge an oily LIPID secretion. Lipids are fats and oil is fat.
They are simple branched alveolar glands that secrete onto one hair follicle.
Contractions of arrector pili muscle cause the release of SEBUM onto the hair follicle and skin surface.
What is sebum? Describe it.
Sebum is a mixture of triglycerides, cholesterol, proteins, and electrolytes.
Sebum LUBRICATES the hair shaft and is ANTIMICROBIAL
Merocrine secretion “mero” means “pure” in LATIN, pure water?
Merocrine glands produce watery secretion. They are sweat glands. Their myoepithelial cells (“myo” meaning muscle) squeeeeeze the gland to discharge secretion..
Their functions to wash the epidermal surface.
There is another type of sweat gland…. can you think of it?
Another type of sweat gland. Not a merocrine sweat gland. What is it called and talk about it.
Apocrine sweat glands!
Not found everywhere! Only in armpits (axillae), groin, and nipples.
They produce a viscous secretion with a COMPLEX composition.
They can communicate olfactory information with their PHEROMONE PRODUCTION.
Strongly influenced by HORMONES.
INCLUDES THE CERUMINOUS GLANDS AND MAMMARY GLANDS
*How to identify? Their DUCT merges with the hair follicle!
Detailed information on ECCRINE/MEROCRINE sweat glands
Found in MOST areas of skin. Not armpits, groin, or nipples!
Produce watery secretions with electrolytes.
Controlled primarily by NERVOUS SYSTEM.
Important in THERMOREGULATION and EXCRETION
SOME*** antibacterial action
Duct opens onto the body surface… we call that a PORE
Detailed info about NAILS. Talk about the nails.
Nails protect the exposed DORSAL surfaces of tips of fingers and toes.
They help limit distortion of digits under physical stress.
Are composed of dead cells packed with keratin.
Can be affected by conditions that alter body METABOLISM.
(If your metabolism gets f’d up, the condition of your nails can be an indication)
EX: diagnostically, if we see nails that are pitted and distorted… it could be that the person has PSORIASIS.
EX: diagnostically, if we see nails that are concave, the person could have a BLOOD DISORDER.
nail structure. what is the main part? talk about it.
The main part of the nail is the NAIL BODY.
It is bordered by LATERAL NAIL GROOVES (depressions) and LATERAL NAIL FOLDS (ridges).
The nail body covers the NAIL BED (the underlying epidermis).
The LUNULA is the pale, proximal part of the nail body.
What is the nail root? Talk about it.
The nail root is the epidermal fold where NAIL PRODUCTION OCCURS.
What is the eponychium? AKA THE ________?
What is the hyponychium?
The “eponychium” (“epi” - over, “onyx” - nail)
the portion of the stratum corneum of the nail root that extends over the nail. AKA THE CUTICLE.
The “hyponychium” is the area of thickened stratum corneum under the free edge.
Getting older… what are the age-related changes in SKIN!!!
Fewer melanocytes.
Thinning, drier epidermis.
Thinning dermis.
Diminished immune response.
Decreased participation.
Reduced blood supply.
Slower skin repair.
Fewer active follicles.
Altered hair and fat distribution.
ratio of melanocytes to basal cells varies by body region. give two ratios
1:4 over most of body
1:20 over palms of hands, soles of feet
The actual NUMBER of melanocytes does not dictate the differences in
SKIN COLOR
malignant melanoma extremely invasive due to extensions of _______. and if they extend into the dermis, you’re in really bad shape.
dendrites; dendritic extensions.
Carotene is what vitamin?
A. Orange VEGETABLES, NOT FRUIT. I REPEAT, NOT FRUIT.
Ingest extra carotene, will invade your fat cells. Accumulates in epidermis and fatty tissues of hypodermis. Vitamin A is a oil-based vitamin. Why you can store them in your body more easily if you have more fat, or adipose tissue. Can reach toxicity.
Why you look orange.
More hemoglobin in your red blood cells =
Skin looks more pinkish. Hemoglobin varies with amount of oxygen binding.
More oxygen binding, bright red. Less oxygen: dark red.
Appears blue (cyanosis) an indicator of poor blood supply. Can be seen in thin skinned areas.
Dilation or constriction of dermal blood vessels can affect
blushing… observed skin coloration. Or if you turn very pale, constriction.
UV Radiation stimulates
Stimulates melanocytes to produce more melanin
skin cancers start in the
epidermis. if they metastisize, they spread into the dermis.
constant sun exposure can increase your risk.
Basal cell carcinoma
most common skin cancer. Most people survive, due to UV radiation. Virtually no metastasis.
Second most common type of skin cancer
Squamous cell carcinoma
Deadly if untreated
Malignant melanoma
cancerous melanocytes, metastasize through lymphatic system. Detected early, 5-year survival rate. If caught late, survival rate 5-10%.
conditions affecting skin color
albinism - genetic mutation causes lack of melanin production or melanin that is extremely light in color.
vitiligo - loss of melanocytes usually due to an autoimmune response those areas of no melanocytes are unprotected from UV radiation.
alopecia - loss of hair.
name two pigments contained in the epidermis
hemoglobin and melanin
why does the skin of a fair-skinned person appear red during exercise in hot weather?
vasodilation
what condition would occur if a person did not produce melanin?
vitiligo, albinism, gray or white hair
Marfin’s syndrome
Disorder of body’s production of collagen fibers and elastic fibers. Your skin just “hangs” on you. You have a weak aorta, your joints are abnormally long. Affects the structure of your entire body.
Merkel cells are what type of touch?
fine touch
tactile corpuscles
go up in to the dermal papillae!!! (epidermis)
… but they are anchored from down in the dermis
(SO BOTH EPIDERMIS AND DERMIS)
vellus hair
think “velvet”, soft finer hairs as opposed to the much coarser, thicker, terminal hairs.
in a hair follicle the epidermis (stratum basale) is actually dipping down into the
DERMIS, where it extends down with the hair bulb, because the root of the hair is alive. The rest of the hair is dead. So, the follicle is alive, everything else is dead.
What coordinates integumentary system function with OTHER systems?
(Endocrine functions - integumentary system)
HORMONES
Glucocorticoids are another name for
Steroid hormones
Steroid hormones, describe function.
(Endocrine functions - integumentary system)
Loosen intercellular connections and reduce epidermis effectiveness as a barrier to infection.
aka glucocorticoids, help us control inflammation in body. too much production of glucocorticoids loosens those intercellular connections… suppresses immunity.
Thyroid hormones, describe.
(Endocrine functions - integumentary system)
Maintain normal blood flow to papillary plexus.
thyroid hormones are your metabolism hormones. targets your mitochondria, tells them to make ATP. if you don’t have enough thyroid hormone you’re not making enough ATP - that’s why you’re tired!
nails are thin and brittle etc etc
Epidermal growth factor (EGF), describe.
(Endocrine functions - integumentary system)
Peptide that has widespread effects on epithelia.
Produced by salivary glands and glands in duodenum.
Functions
Promote cell division in stratum basale and spinosum.
Accelerate production of keratin
Stimulate epidermal development and repair
Stimulate synthesis and secretion in glands
Growth hormone, describe.
(Endocrine functions - integumentary system)
Stimulates fibroblast activity and collagen production.
Stimulates germinal cell division.
THICKENS epidermis.
Promotes wound repair.
widespread effects in body… stimulates bone growth, can produce more actin/myosin strands in body, making your muscles look bigger. known as HGH… hair will grow better, skin will look better. can reverse osteoporosis. known as the “fountain of youth” drug - injections with this drug work but it may stimulate certain types of cancer.
if you take it and your growth hormones are normal though, you can develop acromegaly.
Sex hormones, describe.
(Endocrine functions - integumentary system)
Increase epidermal thickness.
Accelerate wound healing.
Increase number of dendritic cells protecting against cancer cells and pathogens.
Production of Vitamin D
(Endocrine functions - integumentary system)
So production of Vitamin D, produced by a hormone first… goes from steroid hormone to cholecalciferol.
TWO SOURCES: SUNLIGHT AND/OR DIET
SUNLIGHT:
UV radiation causes epidermal cells of stratum spinosum AND basale to convert steroid to CHOLECALCIFEROL.
Liver creates intermediate product then converted to CALCITRIOL by kidneys.
***Calcitriol allows calcium and phosphate to ABSORB IN THE INTESTINE.
(Calcitriol is the active form of Vitamin D).
DIET:
Naturally from fish, fish oils, and shellfish.
From fortified food products.
NO VITAMIN D = NO CALCIUM ABSORPTION… so if taking a calcium supplement, make sure it also contain vitamin D
Vitamin D deficiency in children results in a condition.. what condition?
Rickets.
Condition resulting in poorly mineralized bones.
Develops from not enough sunlight or not enough dietary cholecalciferol (uncommon in US). must take a supplement like Ensure (etc)
In elderly, skin production of cholecalciferol decreases by 75%!
(supplement/diet becomes more important!)
its why cereal, milk, orange juice, is all fortified with vitamin D, its stuff kids eat a lot of… so they fortify these products with vitamin D so calcium can be absorbed.
Skin repair - Steps of regeneration after injury
- Initial injury
bleeding
mast cells cause inflammation - After several hours
blood clot (scab) forms
macrophages patrol/phagocytize debris and pathogens.
stratum basale cells rapidly divide and migrate to wound. - GRANULATION TISSUE forms (blood clot, fibroblasts, formation of extensive capillary network) after one week.
parts of blood clot dissolve
fibroblasts create more collagen fibers and ground substance. - After several weeks
scab sheds
epidermal repair completes
SCAR TISSUE created by fibroblasts raise up epithelium.
Replaces damaged accessory structures of skin, if needed.
on the subject of skin repair, what is a “keloid”
keloid is a thickened mass of scar tissue.
grows into surrounding dermis.
most often in dark-skinned adults.
children scar more easily than adults,
Burns - 1st degree and second degree are
PARTIAL THICKNESS
1st degree (mild sunburn)
2nd degree (blisters, stimulated mast cells)
Burns - Third degree
FULL-THICKNESS - skin graft needed, sensory receptors gone, so it will hurt initially but you won’t have any feeling/pain.
Burns - Fourth degree
Full thickness AND affect deeper structures
Skeletal System FUNCTIONS
- support
- protection
- movement/leverage (in conjunction with musculoskeleton system )
- electrolyte and acid-base balance
- storage (ex. long bones filled with adipose tissue)
- blood cell production AKA hematopoiesis
bone shapes
two types of bone markings, what are they and describe them.
projections AKA processes: grow out from the bone
depressions AKA cavities: indent the bone
two types of bone markings, what are they and describe them.
projections AKA processes: grow out from the bone
depressions AKA cavities: indent the bone
Name (3) joint projections and give their definition.
- condyle: rounded articular projection
- head: bony expansion on a narrow neck
- facet: smooth, nearly flat articular surface
name (6) ligament/tendon projections and give their definition.
- crest: narrow ridge of bone (a “line” is smaller than a crest)
- epicondyle: raised are on or above a condyle
- tubercle: small rounded projection
- tuberosity: large rounded or roughened projection
- trochanter: very large, blunt projection (only on femur)
- sane: sharp, pointed projection
what do “depressions” allow
(bones)
depressions allow blood vessels or nerves to pass through.
name (8) depressions and give their definitions.
- meatus: canal or tube
- fossa: shallow basin
- fissure: narrow, slit-like opening
- sinus: cavity within a bone; filled with air and lined with mucous membranes
- foramen: round or oval opening
- fovea: a small pit or depression for ligament attachment
- sulcus, groove, or furrow: a shallow depression
what is a fovea?
a fovea is in reference to bone anatomy. it is a small pit or depression for ligament attachment.
Bone tissue has a dense ______, containing what?
extracellular matrix
protein fibers
mineral deposits
cell populations
Canaliculi
narrow, long spaces that house osteocyte cell extensions. Bone differs from cartilage in that the extensions of bone cells are in contact with one another through the canaliculi, or “little canals.” Instead of diffusing through the hard, mineralized matrix, nutrients/gases can pass through the small amount of fluid surrounding the cells in the canaliculi and lacunae or pass from cell to cell through the gap junctions connecting the cell extensions.
One very important mineral component of the bone matrix is ___________.
Hydroxyapatite, inorganic material consisting of a calcium phosphate crystal.
Protein fibers like collagen are also an important part of the matrix.
What are osteoblasts?
They are immature bone cells. They are involved in a process called osteogenesis. They produce osteoid and will become osteocytes.
they are bone-building cells. “b” for build. they produce collagen. The formation of new bone by osteoblasts is called OSSIFICATION or OSTEOGENESIS.
What are osteocytes?
They are mature bone cells that reside in lacunae.
They are between layers of matrix (lamellae)
They’re have canaliculi (they’re cell extensions are housed in canaliculi, osteocytes are in contact with each other through these little canals)
Osteoprogenitor Cells
are mesenchymal cells
are located in the endosteum
they aid in repair of fractures
these stem cells can become osteoblasts or chondroblasts - they are the source of new osteoblasts or chondroblasts
origin of bone cells
mesenchymal cells –> osteoprogenitor cells –> osteoblasts –> produce matrix –> osteocytes
osteoclasts
secrete protein digesting enzymes and acids
they are multinucleate cells
osteolysis
different origin than other bone cells
*responsible for bone REABSORPTION (broken down and reabsorbed into the bloodstream Ca++)
They are massive, multinucleated cells.
homeostasis
bone build up and bone recycling must occur at equal rates
more breakdown = bone weakens
more buildup = bone mass increases
what is osteogenesis? aka
aka ossification
formation of new bone by osteoblasts
what is calcification of bone?
when hydroxyapatite crystals and proteoglycans are deposited on the collagen fibers in the organic matrix of bone
what is ossification of bone? what are the different types?
ossification is
- endochondral ossification
- intramembranous ossification
only place where hair growth occurs
hair root
cortex, medulla, cuticle of hair follicle is all
keratin! its layer of keratin on keratin on keratin
a hair that is attached and is no longer growing is called
“club hair” - most of your hair right now
eccrine/merocrine glands most important for
thermoregulation
apocrine sweat glands
produce a scent - BO or pheromone, we try to cover up these glands with deodorant.
ceruminous glands produce earwax. they are ALSO APOCRINE glands. So are mammary glands.
age-related changes - these two things thinning
thinner, drier epidermis
thinning dermis
axial skeleton - # of bones
appendicular skeleton - # of bones
(rough count, # can change based on individual)
axial 80
appendicular 126
skull bones considered
flat bones
sutural bones
small person or a child… helps to detect that… another name for this type of bone is called a
Wormian bone!
LONG BONES
phalanges, humerus obvious one
sesamoid bone
only one you’re supposed to have is patella
compact bone aka
spongy bone aka
compact bone aka dense bone
spongy bone aka cancellous bone
cancellous bone or spongy bone is the site of
hematopoiesis, or red blood cell formation
in long bones, spongy bone found in (15:00 min)
epiphysis… (review)
structure of a long bone with no labels, make sure you know
metaphysis you have what’s called an
epiphyseal line, or epiphyseal disc. depends on how old you are.
two different epiphysis
proximal and distal
lose your articulating hyaline cartilage on long bone, that is
bone on bone
periosteum
made of dense irregular connective tissue. allows for tendons/ligaments (which are straight, dense regular CT) to grow right into the dense irregular CT of the periosteum - or tendon/ligament attachment
cavity in long bones (center) called what? describe.
medullary cavity… what we can pack in the cavity is called “MARROW”
when you’re a child its RED bone marrow.
when you grow up it becomes YELLOW (last resort energy storage, it’s adipose in there - not used unless you’re starving)
endosteum
lines the medullary cavity, contains osteoprogenitor cells (type of stem cell)
why more red bone marrow when you’re a baby?
because you need to grow! you’re constantly making more and more blood when you’re a baby
when you’re 100 years old, your bones are only
20 years old
metaphysis has a _____ or a _______.
plate or a line
if you’re a child, you have a PLATE OR DISC (it is hyaline cartilage). its thick. helps you to grow in height and length
characteristics of bone tissue
dense matrix
protein fibers (collagen - gives tensile strength)
mineral deposits
different types of cells - osteocells, osteoblasts, osteoclasts
channels (called canaliculi) waste passage and transfer of nutrients
canaliculi
periosteum - source of many cells
mineral component of bone matrix, makes bones hard
hydroxyapatite
________ gives bone the ability to _________ while __________ gives it its strength.
collagen, flex (like rebar in construction, allows it to flex a little, TENSILE STRENGTH).
Tensile strength is the ability to flex without shattering.
Hydroxyapatite (like concrete).
Bake a bone, what happens?
It denatures the protein fibers (collagen) and the bone will end up just shattering if any force placed against it
Boil a bone in vinegar, what happens?
Vinegar dissolved the calcium (hydroxyapatite) and you’re left with just collagen. Collagen is strong but bendy (tensile strength) so it bends
Osteoid is
the PROCESS of building a bony matrix
Osteoprogenitor cells are gonna produce you more
osteoblasts, which build bone
Osteoclasts are responsible for
bone remodeling and bone reshaping. “Clasts” - chew
Osteoblasts, describe.
immature bone cell
osteogenesis (means the creation of bone)
security hydroxyapatite and make collagen fibers
produce osteoid
become osteocytes, once they mature (47:30 lecture 9/14)
they produce canaliculi and those “little canals” join in order to get nutrients and waste back and forth through the central canal, where blood vessels are
Osteoprogenitor cells, describe.
mesenchymal cells —> osteoprogenitor cells
stem cells that produce new osteoblasts when needed (can also make chondroblasts)
located in the endosteum AND underneath the periosteum
aid in repair of fractures, also help when building strength/maintaining skeleton
osteoclasts
secrete protein digesting enzymes and acids (trying to digest the protein collagen, also dissolving the hydroxyapatite - strong enough to dissolve through sheet metal!!!)
osteolysis (lysis means to burst or breakdown)
different origin than other bone cells, don’t know exactly where they come from!
homeostasis of bone
equal buildup and equal “builddown” or bone recycling, must occur at equal rates.
more breakdown = weakens your bones
more buildup = bone mass increases
acromegaly
too much bone buildup, bones get too heavy and dense
OSTEON is what
the functional unit of bone
what is an OSTEOID
The PROCESS of building a bony matrix
Perforating canals or Volkmann canals
throughout the dense bone, they are the veins/arteries that travel in a TRANSVERSE fashion. so you have tubules traveling up and down and you have tubules traveling across in a type of blood vessel lattice, or framework.
cancellous bone doesn’t have what compared to dense bone
no central canal needed as in dense bone. trabeculae is surrounded by blood so exchange of nutrients/wastes is very easy.
Spongy bone consists of
Trabeculae.
trabeculae, which are lamellae that are arranged as rods or plates. Red bone marrow is found between the trabuculae. Blood vessels within this tissue deliver nutrients to osteocytes and remove waste. The red bone marrow of the femur and the interior of other large bones, such as the ilium, forms blood cells.
osteogenesis means
the creation of bony matrix.
calcification is a requirement for osteogenesis but the CONVERSE IS NOT NECESSARILY TRUE.
fetal skeleton is
hyaline cartilage and dense regular connective / irregular connective tissue (see recording at 1:14:00)
Intramembraneous ossification can’t be finished yet at birth because
you need to fit through the birth canal… allows soft spots in the skull so you can squeeze through the birth canal and there can be some malleability with the skull bones so it can compress as it passes through. those soft spots are called FONTANELS
What are the major functions of the skeletal system?
body support - cartilage, ligaments
organ protection - for example, skull protects brain
body movement - tendons, joints, ligaments
mineral storage - (calcium and phosphorous are the big ones, also adipose tissue)
blood cell production - contain cavities filled with red bone marrow, gives rise to red bone marrow and platelets
How does the skeletal system function in protection?
skull encloses and protects brain, vertebrae surround and protect spinal cord, rib cage protects heart, lungs, and other thoracic organs
all about endochondral ossification
- Chondroblasts produce a cartilage model that is surrounded by perichondrium, except where joints will form.
- The perichondrium of the diaphysis becomes the periosteum, and a bone collar is produced. Internally, the chondrocytes hypertrophy, and calcified cartilage forms.
- A primary ossification center forms as blood vessels and osteoblasts invade the calcified cartilage. The osteoblasts lay down bone matrix, forming spongy bone.
- Secondary ossification centers form in the epiphyses of long bones.
- In a mature bone, the epiphyseal p late has become the epiphyseal line, and all the cartilage in the epiphysis, except the articular cartilage, has become bone.
all about intramembranous ossification
also know fontanels, they are associated with this concept
structure of a long bone
listen to audio
long bone, gross anatomy terms
diaphysis
epiphysis
periosteum
endosteum
articular cartilage
epiphyseal plate
spongy bone
medullary cavity
red marrow
yellow marrow
all about the periosteum
all about the endosteum
comparison between intramembranous and endochondral ossification
bones ossify in women around puberty to get women ready for
CHILDBIRTH
ENDOCHONDRAL GROWTH (VS ENDOCHONDRAL OSSIFICATION)
affect of growth hormone on epiphyseal plate.
appositional growth is
GROWTH IN WIDTH (as opposed to LENGTH) that’s why when someone has too much growth hormone has acromegaly where body parts don’t look proportional, they look wider…
skull growth is all
appositional…
long bones also experience appositional growth because not only do they get longer, they also have to get wider
Vitamin K is used to
clot blood
calcium homeostasis
must be regulated very tightly (needed for neurons firing, muscles contracting - therefore heart contraction)
2 hormones needed to determine your body has “just right” levels of calcium through a NEGATIVE FEEDBACK SYSTEM
calcitonin released when blood calcium levels too high…
PTH hormone will be decreased. Small intestinal absorption will decrease. Calcitonin will go to kidneys and say “hey kidneys, urinate that stuff out.” Osteoclasts inhibited while osteoblasts continue to lock calcium ions in bone matrix. Will only occur if you do WEIGHT BEARING EXERCISE. IF YOU DON’T YOU KNOW HERE YOUR CALCIUM GOES??? POOPING AND PEEING IT OUT. Your body will only lock the calcium in your bone matrix if your body thinks you need it - which it will need if you do weight bearing exercise. Too high of calcium can lead to kidney stones.
PTH (parathyroid hormone) released when calcium blood levels are too low… (says “hey, small intestine, absorb more Ca++ and put it into the bloodstream” - also says “hey kidneys, reabsorb more calcium before releasing it into the urine” THESE TWO THINGS CAN ONLY HAPPEN IF YOU EAT CALCIUM AND IF YOU HAVE VITAMIN D… If you’re not eating calcium, your body will target the bones and your osteoclasts will “chew” or stimulate the release of calcium ions from bone
Bone fractures (will be tested more on bone healing) but
Classification of fractures - 3 descriptives
- location
2 nature of break - external appearance
external appearance of a bone fracture can be one of two ways:
- closed (simple)
- open (compound)
transverse fracture is
the way we WANT OUR BONES TO BREAK! It’s a break across the shaft of the bone.
Comminuted fracture
is bad bc it’s right down there at the joint. if a child gets this type of break, then the epiphyseal plate will be forced to grow into a line, preventing growth (bad for kids)
greenstick fracture
common in wrists
spiral fracture
happens in rotation, happens a lot in basketball. a twisting motion.
colles fracture
common in wrist
pott’s fracture
down there in the ankle
epiphyseal fracture
BAD ONE IF YOU’RE A CHILD. That plate that separates the two bones, that’s where the bones are separated.
fracture repair at 28:30 9/15/22
extra HGH
gigantism
too much growth hormone after epiphyseal plates have fused
acromegaly
decrease in bone strength
osteopenia
bone is porous, bone won’t support weight as well
osteoporosis
genetic issue where collagen is not made correctly. bone’s have the hard part, the hydroxyapatite, but they don’t have the collagen fibers - so the bone has NO TENSILE STRENGTH so bones just shatter and break like glass.
ostegenesis imperfecta
joint are known as
ARTICULATIONS - functional junction between bones
Epiphyseal disc is actually a
joint!
structural classification of joints
fibrous - not lots of movement
cartilaginous - between vertebra is example
synovial - most complex, allow for free movement (what you think of when you think of a joint)
functional classification of joints
how moveable the joint is
(fibrous joint) synarthrosis or synarthrotic joint - considered immoveable.
(cartilagenous joint) amphiarthrotic joint - slightly moveable
(synovial joint) diarthrotic joint - freely moveable
S.A.D. —-> LEAST MOVEABLE TO MOST MOVEABLE
Synarthrosis, Amphiarthrosis, Diathrosis
3 types of fibrous joints
Syndesmosis - type of fibrous joint in which two parallel bones are united to each other by fibrous connective tissue. Ex: Lies between tibia and fibula
Suture - between flat bones. Thin layer of CT. Skull is example.
Gomphosis - tooth in jawbone (think “gum”) cone-shaped bony process in socket. considered immovable but they can move a LITTLE BIT.
Cartilaginous joints (2)
Synchondrosis: bands of hyaline cartilage that unite bones. Epiphyseal plate (temporary) Between manubrium and the first rib - not freely moveable
Symphysis: pad of fibrocartilage between bones. Also your pubic symphysis. Joint between Bodies of adjacent vertebrae. Shock absorption and a little bit of bend.
Synovial joints, in detail describe.
Freely moveable (diarthroses)
6 types of diarthroses
Specific parts of a diarthroses:
1. articular cartilage
2. joint cavity
3. joint capsule
4. synovial membrane
5. synovial fluid - lubrication for joint
6. meniscus -
7. bursae -
largest, most complex joint in body is the
KNEEEEEEEEEEEEEEEEEEEE
pivot joint example
SYNOVIAL JOINT
Between atlas (C1) and
the dens of axis (C2)
Hinge Joint
SYNOVIAL JOINT
• Elbow joint
• Between phalanges
Saddle Joint
SYNOVIAL JOINT
Between carpal and 1st
metacarpal (of thumb)
Condylar Joint
SYNOVIAL JOINT
• Between metacarpals and
phalanges
• Between radius and carpals
Ball-and-Socket Joint
SYNOVIAL JOINT
• Hip joint
• Shoulder joint
Gliding Joint
SYNOVIAL JOINT
• Between carpals
• Between tarsals
• Between facets of
adjacent vertebrae
Movement at a joint occurs when
a muscle contracts
and its fibers pull its moveable end (insertion) towards its
fixed end (origin).
abduction/adduction
flexion/extension/hyperextension
flexion/extension
dorsiflexion/plantar flexion
circumduction
medial rotation and lateral rotation
supination/pronation
Inversion/Eversion
protraction/retraction
elevation/depression
when you see a skeleton in lab all put together, that is a ________ skeleton. If you see the individual bones of the skeleton that is a _________ skeleton.
articulated
disarticulated
A fibrous joint is what kind of tissue
dense connective tissue
what type of cartilage makes up cartilaginous joints?
hyaline cartilage and fibrocartilage are the two types of cartilage
wormian bones come together where
the soft spots were located, or fontanels… the sutures are where fibrous connective tissue came together… (suture, synarthrotic, fibrous joint)
intervertebral discs are examples of what type of joint, what type of cartilage?
amphiarthrosis, symphysis - (cartilaginous joint)
costal cartilage is an example of what type of joint
it is a synchondrosis, (1 of 2) cartilaginous joints, amphiarthrotic
bursae
closed sacs that are lined with synovial membrane, serve as a cushion between tendon and bones
main example of a pivot joint (“say no with head”)
atlas and axis
hinge joint only one type of action
flexion and extension (knee, elbow)
saddle joint
allows for “rocking in the saddle”
carpal and 1st metacarpal of thumb is a saddle joint
*allows your thumbs to be opposable
Condylar joint
between your digits (your metacarpal and your carpal)
Ball and Socket Joint
hip joint, shoulder joint
have most movements possible!!!! can go in all directions! joint construction is a little looser to allow for all those different movements.
it’s why shoulder sockets gets dislocated so easily. make sense? good.
gliding joints
(aka plane joints)
between carpals, facets of wrist
two flat planes that can slide or glide across each other.
For Adduction, think this
I’m “ADDING” it back to the body
Dorsiflexion
TOES UP
Plantar flexion
Ballerina toes (pointed)
flexion always
DECREASES THE ANGLE between two muscles
difference between rotation and circumduction
think “circumference” - drawing a circle
rotation is “pivoting” on a point
supination of hands
you can walk around and “carry your soup”
palms are up
inversion - your tipping it
“inward” - medially
