Exam 3 Study guide A&P

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what is the epidermis?

most superficial layer of skin; separated from dermis by basement membrane

cells in epidermis?

keratinocytes, melanocytes, langerhans cells, merkel cells

what is the function of keratinocytes?

resist abrasion and reduce water loss

what is the function of melanocytes?

give skin its color

what is the function of langerhans cells?

pathogen detection for immune cells

what is the function of merkel cells?

detect pressure

layers of epidermis from deepest to superficial

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

where is thick skin found?

palms and soles of feet

where is thin skin found?

where hair is found

what does thick skin contain?

all 5 strata (layers of epidermis)

which layer does thin skin lack?

stratum lucidum

which cells gives skin its pigment?

melanocytes

where is the dermis found?

below the epidermis

what is the function of the dermis?

skin strength

the dermis is the location of what?

nerve endings on skin

nerve endings detect which type(s) of pressure?

pain, itch, tickle, and temperature sensations

Pacinian corpuscles detect which type(s) of pressure?

deep pressure

Meissner corpuscles detect which type(s) of pressure?

light touch, stimulation at 2 different points

Ruffini end organs detect which type(s) of pressure?

continuous touch, stretching, tension of skin

what are the 2 layers of the dermis?

papillary and reticular

what does the papillary layer of the dermis contain?

blood vessels, friction ridges (forms unique fingerprints)

what forms on the reticular layer of the dermis?

stretch marks

which layer is the main layer of the dermis?

reticular

which tissue is NOT apart of the integumentary system?

subcutaneous tissue

what is the function of subcutaneous tissue?

attaches skin to bone and/or muscle

what are the stages of hair development in order? (earliest to oldest)

lanugo, vellus hair, terminal hair

where is the hair shaft found?

above the surface of skin

where is the hair root found

below the surface of skin

what is at the base of the hair root?

hair bulb

what does the hair matrix contain?

stem cells

which part of the hair is the arrector pili muscle associated with?

hair follicles

what does a merocrine gland do?

uses exocytosis to secrete substances, gland isn’t damaged at all

what does an apocrine gland do?

top part of gland builds product then pinches off to release

what does a holocrine gland do?

gland fills with oily products until it ruptures and died to be excreted

Which major gland is in sebaceous glands?

holocrine

What is sebum?

oily lipid-filled substance

what is the function of sebaceous glands?

produces sebum onto hair follicles, prevents drying off hair and protection against bacteria

which major gland is in ceruminous glands?

merocrine

what gland is modified to form ceruminous glands?

eccrine sweat glands

where is the ceruminous glands located?

in ear canal

what do the ceruminous glands produce?

cerumen (earwax)

what is the function of ceruminous glands?

protect tympanic membrane by preventing dirt and insects from moving into ear canal

which major gland is in mammary glands?

apocrine

where are the mammary glands located?

breasts

what is the function of mammary glands?

produce milk, inactive until female gives birth

what are the two major types of sweat glands?

eccrine and apocrine

what is the function of eccrine glands?

open directly on skin surface move water and salt through duct to help body cool down when temperatures increase

where are apocrine glands found?

in axillae and genitalia

what do nails consist of?

dead stratum corneum and hard keratin

what does the nail matrix contain?

like hair, cells for growth

what is the hyponychium in the nail?

thickened region of corneum cells beneath free edge

what is the free edge of the nail?

skin beneath cell

what is the lunala of the nail?

part of matrix that appears white from lack of blood vessel visibility

what are the 5 physiology aspects of the integumentary system?

protection, sensation, temperature regulation, vitamin D production, excretion

what type of cartilage is present in joints that covers the ends of bones?

articular cartilage

what does the bone matrix consist of?

mostly inorganic and organic material

What does inorganic material in bones consist of?

minerals and calcium

what does organic material in bones consist of?

collagen and proteoglycans

what is an osteoblast?

bone building cell; necessary for ossification

what is an osteocyte?

converted from osteoblasts; cells of bone; located in lacunae

what is an osteoclast?

break down bone; done when calcium is needed elsewhere in the body

what is an osteon?

functional unit of bone

what is the function of the lacunae?

house osteocytes

what is the canaliculi?

extension of osteocytes; connect bone cells to one another

what is the lamellae?

concentric layers of bone; only found in compact bone

what are the 3 different types of lamellae?

concentric, interstitial, circumferential

what are the concentric lamellae?

rings of lamellae that form around central tunnel

what are interstitial lamellae?

layers located between osteons

what are circumferential lamellae?

surround entire bone

what is the haversian canal?

central tunnel; contain nerves and blood supply for osteons

what is the perforating (Volkmann) canal?

perpendicular routes within bone carrying blood to haversian canals

what is the trabeculae?

interconnecting rods/plates found in spongey bone

what is appositional growth?

new cartilage added to outer aspects of existing cartilage

what is interstitial growth?

new cartilage added in the center of the matrix

what is resorption?

where osteoclasts break down bone tissue

how does resorption work?

lowers pH to dissolve inorganic material; material is transferred to blood stream

What are the characteristics of spongy bone?

appears porous; less bone matrix and more space than compact

what are the characteristics of compact bone?

more bone matrix; less space than spongy bone

where is compact bone found?

outside of bone

where is spongy bone found?

at the end of long bones

what is the diaphysis in long bones?

center portion of bone; mostly compact bone; surround medullary cavity

what is the epiphyses in long bones?

ends of long bones; mostly spongy bone with outer layer of compact bone

what is the role of the epiphyseal (growth) plate?

location where growth of bone occurs; once growth stops, becomes ossified and the epiphyseal line

what is periosteum?

attachment site for tendons and ligaments

what are the 4 different types of bones?

long, flat, short and irregular

what is a long bone?

bone with central shaft and 2 ends; longer than it is wide

what is a flat bone?

spongy bone sandwiched between 2 layers of compact bone

what are short and irregular bones?

compact bone surfaces surrounding spongy bone; small cavity in the middle; no diaphysis

what are 3 factors that affect bone growth?

genetics, nutrition, and hormones

which 3 hormones contribute to bone growth?

growth, thyroid and reproductive

how is bone strength increased?

through mechanical stress

what are the 4 steps of bone repair?

hematoma formation, callus formation, callus ossification, bone remodeling

which 3 hormones play a role in calcium homeostasis?

PTH, calcitriol, calcitonin

what does the PTH hormone do?

activate osteoclasts to remove calcium from bone; secreted when blood calcium levels are low

what does the calcitriol hormone do?

increase osteoclast activity

what does the calcitonin hormone do?

inhibit osteoclast activity

what are the 3 structural classifications of joints?

fibrous, cartilaginous, synovial

what are fibrous joints?

connections between 2 bones held together by connective tissue; no movement

what is a suture?

interlocking processes for stability; found in skull

what are syndesmoses joints?

contains interosseus membrane between bones; slightly movable; found where joints are further apart