Lecture Quiz 3 Flashcards
What are the main characteristics of connective tissues?
arise from a type of embryonic tissue - mesenchyme
cells lack intercellular contact
surrounded by large amounts of extracellular matrix consisting of protein fibers and ground substance
well vascularized with the exception of cartilage
What are the functions of connective tissues?
structural framework (bone, cartilage)
transport of nutrients and waste (blood)
protection (bone, cartilage, adipose)
support and interconnection (tendons, ligaments, capsules)
insulation and energy storage as well as production of important cells of blood and lymphatic tissues (adipose, bone marrow)
body defense and repair (blood, lymph, dense ct)
Describe the extracellular matrix
includes all materials surrounding the cells
consists of ground substance and protein fibers
product of specialized cells
What is the relationship between connective tissue and extracellular matrix?
the function of connective tissue is determined by composition of the extracellular matrix
What is the ground substance?
a mix of extracellular fluid, mucopolysaccharides, glycoproteins, minerals, and other substances
can be fluid, gel-like, or solid
fibers include collagen, elastic, and reticular fibers
Describe collagen fibers
the strongest of the fibers with only 3% stretch
ligaments and tendons are mostly made of collagen
Describe elastic fibers
composed of protein, but exhibit significant recoil when stretched
most structures that exhibit elasticity contain elastic fibers
Describe reticular fibers
protein fibers that are lacy and fragile
most lymphoid structures such as lymph nodes, spleen, tonsils, Peyer’s patch contain significant amount of reticular fibers
the residence for many of our immune cells
Describe cell development in the connective tissue
all cells develop from a common presursor - mesenchymal cells - that differentiate into tissue-specific blast, which in turn mature into tissue specific cells (chondroblasts and chrondrocytes for ex)
What additional cells do connective tissues contain?
adipocyte - store nutrients
mast cells - detect foreign cells and initiate inflammation response by releasing heparin, histamine, and macrophages
macrophages - phagocytic cells that engulf foreign cells
white blood cells may also migrate into connective tissues to assist with immune response
What are the two types of fluid connective tissue?
blood - transports fueld, nutrients, ocygen, and the cells of the immune system throughout the body. Extracellular matrix is called plasma
lymph - formed from the plasma and interstitial fluids draining from the capillary beds
What are the cells of the immune system carried in blood?
erythrocytes (red blood cells)
leukocytes (white blood cells)
Thrombocytes (platelets) - just cellular debris
What are the different types of leukocytes?
granulocytes - neutrophils, eosinophils, basophils
agranulocytes - monocytes, lymphocytes
Describe areolar connective tissue
loose connective tissue
acts as the “packing material” of the body
it is found in all membranes and underlining epithelial tissues
site of immune response
mostly matrix with randomly arranged protein fibers of all three types
abundant intercellular spaces
Describe adipose connective tissue
loose connective tissue
consists of adipocytes, cells that store energy in fat
enlarged droplets of fat push the nuclei and cytoplasm, to the periphery
two types - brown and white
Describe reticular connective tissue
makes up the framework of glands, organs, and lymph nodes
Describe dense regular connective tissue
strongest tissue in the body
makes up the ligaments, tendons, and aponeurosis
collagen fibers run parallel providing additional strength
slow to heal
Describe irregular connective tissues
consists mostly of collagen fibers
has few cells and practically no ground substance
found in protective fascia, fibrous joint capsules, dermis, and hypodermis, pericardium, heart valves
slow to heal
Describe elastic connective tissue
consists mostly of elastic fibers and therefore is capable of stretching
found in arterial walls, lungs, vocal cords, etc
Describe cartilage
supportive connective tissue flexible but strong maintains its shape well collagen fibers are firmly implanted in gelatinous ground substance called chondroitin sulfate - 80% water there are three types of cartilage
What is hyaline cartilage
hyaline cartilage - matrix is rich in strong collagen fibers, which provide support and hyaluronic acid that helps to reduce friction and absorb shock
precursor in bone development
most common type of cartilage
found in the nose, rib cartilage, synovial joins, and epiphysis of the bones
What is elastic cartilage?
elastic fibers found in the matrix give the cartilage exceptional rebound capabilities
found in the external ear, Eustachian tubes, and epiglottis
What is fibrocartilage?
contains fine collagen fibers arranged in layered arrays
exhibits exceptional resistance to compression
found in intervertebral disks, menisci of the knee join, and symphysis pubis
Describe osseous tissue
matrix is rich in calcium phosphate which provides strength
two types
Describe compact bone
found in the shafts of long bones and in the outer layer of all other bones
its functional unit is called osteon - consists of matrix deposited in layers (lamella) around a canal containing blood vessels
matrix is produced by the osteocytes
Describe cancellous or spongy bone
does not have an osteon structure
site of the bone growth
surrounds red bone marrow
What does the integumentary system consist of?
skin hair nails sweat glands sebaceous glands
What are the functions of the integumentary system
protection
thermoregulation
vitamin production
excretion of metabolic waste
Describe the skin
largest organ in the body weighs 9 lbs avg surface area is 20 cubic ft two layers - epidermis and dermis a layer of loose connective tissue, hypodermis, can be seen below the skin
Describe the epidermis
consists of keratinized stratified squamous epithelium
this includes keratinocytes, melanocytes, langerhans’ cells, and merkel cells
What are the five layers of the epidermis?
stratum basale stratum spinosum stratum granulosum stratum lucidum stratum corneum
Bad Skin Gets Large Calluses
Describe the stratum basale
deepest layer of the epidermis
consists of a single layer of columnar or cuboidal cells that rest on the basement membrane
cells rapidly proliferate and give rise to all other layers of the epidermis
How long does the renewal of the epidermis take?
3 to 4 weeks
Describe melanocytes
found in the stratum basale
produce melanin
this is then injected into the keratinocytes of the basal layer
protects the chromosomes of mitotically active basal cells against light-induced damage
sun causes production of melanin granules
Describe the stratum spinosum
5-10 layers of tightly interdigitating live cells irregular in shape
Contain the intermediate filament pre-keratin
varies in thickness
Describe the stratum granulosum
3-5 layers of cells that begin to degenerate
they become flat, their nuclei disintegrate, and the cellular membrane thickens
multiple granules of keratin is found in this layer
Describe the stratum lucidum
consists of several layers of lear, flat, dead cells
only visible in thick skin
best seen in palms and soles of feet
Describe the stratum corneum
makes upper 2/3 of the epidermis
20-30 layers of very flat, dead cells make up the most superficial layer of skin
designed for protection
dead cells shed off at roughly the rate at which new cells are produced underneath
Describe the dermis
consists of connective tissues and is found below the epidermal layer of skin
rich in capillaries, nerves, and lymphatic vessels
has two layers
Describe the papillary layer
loose areolar connective tissue
makes nipple-like projections into epidermis (dermal papillae)
dermal papillae with overlaying epidermis make a unique pattern (fingerprints)
Describe the reticular layer
makes up to 80% of the dermis
dense irregular connective tissue
has collagen that provides strength and elastin that provides stretch and recoil
What causes wrinkles?
decreased elasticity of the dermis
resorption of the bone
atrophy of subcutaneous fat
What determines skin pigmentation?
three pigments:
melanin
carotene
hemoglobin
Describe melanin
a dark brown protein pigment produced by melanocytes in the stratum basale that absorbs UV radiation
increased exposure to UV light results in more melanin secretion
varies in color and amount produced
regulated genetically by the pituitary and adrenal glands
How is melanin produced?
from amino acid tyrosine utilizing enzyme tyrosinase
in albinism, this enzyme is absent due to genetic mutation
Describe carotene
a yellow non-polar hydrocarbon pigment produced by vegetables, such as carrots and spinach, and gives skin a yellow shade
How does hemoglobin affect skin pigmentation?
iron-based protein found in the blood
skin is transparent, hemoglobin carries blood to the capillaries of the dermis and gives the skin a pink color
What metabolic process occurs in the skin?
the active form of vitamin D is produced in the skin in the presence of UV light
a small amount of UV light is sufficient
folic acid, which is required for DNA synthesis and is needed in pregnant women, is destroyed by UV light
Describe nails
facilitate grasping by the fingers
analogous to the epidermis
stratume basale gives rise to the entire nail
adheres tightly to the epidermis at the nail bed
Describe the hair
body is covered by vellus hair
skull is covered by terminal hair
avg head has 100,000 hairs, each living 2-4 years
over 5 million hair follicles on the body
hair matrix is analogous to the stratum basale
Describe hair follicles
contain the root of the hair
extends to the upper layers of the hypodermis
its lower portion, the bulb, consists of mitotically active cells
these produce keratin that does not flake off
What is the muscle involved in a hair?
arrector pili
smooth muscle that connects the papillary layer of the dermis and the follicle
causes hair to stand up
Describe sebaceous glands
secrete a lipid-rich material into the upper parts of the hair follicles or onto the surface of the skin
has no softening effect on the skin
very limited antibacterial and antifungal activity
makes the skin water-resistant
liable for acne
What are the two types of sweat glands
Eccrine (merocrine) sweat glands
Apocrine sweat glands
Describe Eccrine (merocrine) sweat glands
produce a secretion containing mostly water and salt
important for regulation of body temperature
sweat is emptied directly onto the surpace of the skin
no damage to cells in gland, therefore no cellular debris
Describe apocrine sweat glands
located in teh axillary and anogenital regions
produce a more lipid-rich secretion that empties into the upper part of the hair follicle
stimulated by sexual hormones
parts of cell are pinches off to release sweat
bacteria feeds on cellular debris, this causes the smell
What are the parts of the skeleton?
axial skeleton - skull, vertebral column, and rib cage
appendicular skeleton - arm, shoulder, and pectoral girdle
What are the functions of the skeletal system?
support movement protection hematopoiesis mineral storage
What are the types of bone?
long - tibia, femur
short - carpals, tarsals
flat - frontal, parietal (skull)
irregular - vertebrae
What are the features of a long bone?
the epiphysis is the end of the bone- outer layer is compact bone, inner layer is spongy
diaphysis is the shaft - a collar of compact bone and a medullary cavity filled with yellow bone marrow
periosteum is outer covering of the bone
Describe the periosteum
consists of a fibrous layer (dense irregular connective tissue) and an osteogenic layer that gives rise to osteoblasts
contains nerves and vessels
serves as a site of bone growth and repair
What are the features of flat bone
spongy bone filled with red bone marrow
surrounded by thin layer of compact bone and covered by the periosteum
Where is bone marrow taken from?
the pelvis
Describe an osteon
functional unit of compact bone
consists of columns with central Harvesian canal that carries capillaries and nerves
perforating volksman canals bring vessels from the periosteum to the central canals
concentric lamella composed of bone matrix and cells surround central canal
Describe the bone matrix in an osteon
organic collagen fibers are oriented in the same direction in each osteon and provide high resistance to stretch
calcium phosphate and hydroxyapatite provide high resistance to stretch
What are the cells of the bone? Describe them
osteoblasts - produce matrix and are not embedded in it, eventually bury themselves and become
osteocytes - mature cells that occupy lacunae and connect with each other thru canaliculi
osteoclasts - reabsorb the bone
How are bones typically broken?
torsional forces
Describe the lamella of osteons
gelatinous matrix
mineral salts hydroxyapatite provide high resistance to stress
collagen fibers oriented in teh same direction in each osteon and provides high resistance to stretch
