Week 4 Flashcards
three types of integumentary structures
Hair, Glands, Nails
three types of hair
Lanugo, Vellus and terminal
Lanugo hair
- fetuses and newborns
- Helps protect delicate fetal skin from amniotic fluid.
- Thicker than vellus hair. After the hairs fall out, they are replaced by vellus hair.
vellus hair
- Replace lanugo hairs shortly after birth.
- Some vellus hairs are replaced by terminal hairs after puberty.
- peach fuzz hair
terminal hairs
- thick, pigmented hairs.
Includes head hair and eyebrow hairs.
three layers of terminal hairs
medulla, cortex, cuticle
medulla
the central core of terminal hair, has air spaces and soft keratin
Cortex
has long thin strands of hard keratin. Where the pigmentation is.
cuticle
outermost layer of thin, flat cells that resemble shingles, mostly hard keratin.
the hair follicle contains
hair bulb, follicle receptor, papilla, arrector pili, sebaceous gland, hair root, hair shaft
hair bulb
deep end of follicle
Hair follicle receptor
(allows hairs to act as touch receptiors)
papilla
a bit of dermal tissue that supplied the growing hair with nutrients from capillaries
what is hair wrapped in
CT
Arrector pili
smooth muscle that causes hair to stand up, creating goose bumps)
Sebaceous gland
lubricates hair, controls bacterial growth)
Hair root
lower part of hair that is attached to skin)
Hair shaft
upper part of hair in follicle that is not attached to skin)
what is hair color produced by
melanocytes at the hair papilla, and determined by genes.
what causes hair shape?
is due to the shape of the hair shaft.
Round hairs have straight texture
round hair
hairs have straight texture
Oval hair
hairs are wavy to curly textured
Flat hair
ribbon like hairs have a kinky texture
Nail matrix
is responsible for nail growth; the rest of the nail is dead
lunula
The lunula is white crescent shaped discoloration at the base of the nail, because it is overlying the nail matrix, which is thick and blocks the pink color of the dermis from showing through.
Leukonychia
are small areas of white discoloration. Usually due to a minor injury of the nail bed
mee’s lines
lines that extend the whole width of the nail can appear after episodes of poisoning, and can indicate renal failure.
Clubbing
is an indicator of heart and lung disease (caused by low oxygen).
- swelling of just the distal section of the fingers
Yellow nails syndrome
thickened, slow growth of nails.
This can be an indicator of respiratory diseases.
what are the two parts of the skeleton
axial and appendicular
axial skeleton
forms the longitudinal axis of the body, includes spine, ribs, head
appedicular
includes limbs and pectoral and pelvic girdles.
what are the functions of the skeleton
supports, stores, hematopoiesis, leverage
what do the bones store?
reservoir of chemicals
stores fat in the yellow marrow
Hematopiesis
red blood cell prodution
leverage
Works with muscles to move body and/or body parts
long bones
most of the bones in the appendicular skeleton
Flat bones
many bones in skull
sagitital bones frontal bone
Irregular bone
vertebra, lower skull bones, sacrum
Short bone
carpal and tarsal bones) roughly cube-shaped
Sesamoid bone
bones are embedded in a tendon or muscle, and form in response to strain. They act like pulleys and provide a surface for tendons to slide over.
structure of long bone
- diaphysis, shaft of bone made of compact bone.
- epiphysis, is the wide part at both ends of the bone, mostly spongy bone
- metaphysis, where the other two parts meets
where is red and yellow marrow found?
red axial, yellow appendicualar
osteon
the structural and functional unit of compact bone.
- thousands of osteons making up the compact parts of bones.
- act like weight bearing pilars
lamellae
are different layers of the osteon/ bones
central canal
contains nerves and blood vessels.
lacunae
, or holes in the bone that osteocytes live in.
Canaliculi
are passages in the bone that filapodia of the osteocytes pass through, to connect to the central canal and to other osteocytes.
filapodia
the connective arms of octeocytes that they use to contact eachother and the central canal
spongy bone
Lamellae are arranged in struts called trabeculae.
Red or yellow marrow can be found between the spaces of the trabeculae.
what are the types of bone cells
osteoprogenitor, osteoclasts, osteoblasts and osteocytes
osteoprogenitor
- divide to produce osteoblasts.
- They are located in the inner, cellular layer of periosteum and endosteum.
- Important in fracture repair.
osteoblasts
- secrete matrix compounds. They make collagen, proteoglycans, glycoproteins that are not yet calcified.
- They mature into osteocytes.
Osteocytes
- mature bone cells that live in the lacunae between lamellae, connected through filapodia that fill the canaliculi.
- They do not divide
- They maintain protein and mineral content of matrix.
osteocytes
come from stem cells that also divide into macrophages.
Marfan syndrome
is a connective tissue disorder that is associated with the overgrowth of long bones.
Rickets
is a softening of bones in childhood due to malnutrition, either a lack of vitamin D or calcium. Leads to bowed limbs, weak muscles, brittle bones.
Osteoperosis
is a weakening of bones associated with old age, caused by an imbalance between osteocytes and osteoclasts.
what are the two kinds of membrane associated with bones
periosteum
endosteum
periosteum
-covers the outside surface of bones (except for articular surfaces)
- has two layers
Contains perforating fibers; tufts of collagen that perforate into the bone. This lets the periosteum serve as a site of attachment for tendons.
what are the two layers of the periosteum
outer fibrous layer and the inner layer
what is the outer fibrous layer made of
r is dense irregular connective tissue
The inner layer of the periosteum
is cellular, contains osteoblasts, osteoclasts, osteoprogenitor cells.
The periosteum helps supply the bone with nutrients (it has nerves and blood vessels)
endosteum
covers the interior of the bones and connects the bone marrow and trabeculae to the bone
when do human bones stop growing.
25
osteogenesis
bone formation
ossification
the process of replacing other tissues with bone.
Calcification
process of depositing calcium salts.
