A&P 1 Exam 2

4 primary tissues

epithelial, connective, nervous, and muscular

3 primary germ layers

ectoderm

endoderm

mesoderm

ectoderm

outer

gives rise to the epidermis and nervous system

endoderm

inner

gives rise to mucous membrane lining digestive and respiratory tracts, digestive glands, among other things

mesoderm

middle

becomes gelatinous tissue called mesenchyme

gives rise to cartilage, bone, blood, muscle

wispy collagen fibers and fibroblasts in gel matrix

tissue sections

Longitudinal- cut on long axis

Cross- cut perpendicular to long axis

Oblique- cut at angle between longitudinal and cross

properties of epithelium

* cover body surfaces and line cavities
* makes up most glands
* avascular
* cells very close together
* basement membrane, basal surface, apical surface
* simple or stratified

simple squamous

* rapid diffusion and transport
* location: alveoli, glomeruli, endothelium, serosa

simple cuboidal

* resists abrasion, retards water loss through skin, resists penetration by pathogens
* location: epidermis, palms and soles

non-keratinized stratified squamous

* resists abrasion (not as strongly as keratinized) and penetration of pathogens
* location: tongue, oral mucosa, esophagus, and vagina

stratified cuboidal

* secretes sweat, produces sperm, produces ovarian hormones
* location: sweat gland ducts, ovarian follicles and seminiferous tubules

transitional

* allows for filling of urinary tract (stretching)
* location: ureter and bladder

simple vs stratified epithelia

simple: touches the basement membrane

stratified: some cells rest on top of each other (not touching basement membrane)

7 types of cells found in fibrous connective tissue.

* fibroblasts
* macrophages
* leukocytes
* plasma cells
* mast cells
* adipocytes

macrophages function

phagocytize foreign material and activate immune system

function of leukocytes

neutrophils attack bacteria, lymphocytes react against bacteria, toxins and other foreign antigens

function of plasma cells

synthesize antibodies (proteins)

function of mast cells

secrete heparin to inhibit clotting and histamine to dilate blood vessels

function of adipocytes

store triglycerides (fat)

what is the matrix of connective tissue

ground substance (interstitial fluid) + collagen/elastic/reticular fibers

functions of collagen fibers

* most abundant protein in body
* tough, flexible, and stretch-resistant
* tendons, ligaments and deep layer of the skin

functions of reticular fibers

* thin collagen fibers coated with glycoprotein
* form framework of spleen and lymph nodes

functions of elastic fibers

* thinner than collagenous fibers
* branch and rejoin each other
* made of elastin
* allows stretch and recoil

areolar connective tissue

* loose connective tissue, highly vascularized
* location: underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels

dense irregular connective tissue

* densely packed, randomly arranged collagen fibers, withstands unpredictable stress
* location: deeper layer of skin, capsules around organs

adipose connective tissue

* space between adipocytes occupied by areolar/reticular tissue and blood capillaries, brown and white fat, energy storage, insulation, cushioning
* location: subcutaneous fat, around organs

hyaline cartilage

* “fish eye soup”, eases joint movement, holds airway open, moves vocal chords, growth of juvenile long bones
* location: articular and costal cartilage, trachea, larynx, fetal skeleton

elastic cartilage

* provides flexible elastic support
* location: external ear, epiglottis

fibrocartilage

* large coarse bundles of collagen fibers, resists compression and absorbs shock
* location: pubic symphysis, menisci, intervertebral discs

blood

* fluid, transports cells and dissolved matter, plasma, Erythrocytes (RBC), Leukocytes (WBC), thrombocytes
* location: veins and arteries

what distinguishes excitable tissues from other tissues

only muscular tissue contracts (via electrical signals) and only nervous tissue can initiate an electrical signal

Nervous tissue cells

* neurons
* neuroglia

junctions that hold cells and tissues together

tight junction, desmosome, gap junction

tight junction

linkage between two adjacent cells by transmembrane cell-adhesion proteins

desmosome

hook-like, j shaped proteins that arise from the cytoskeleton to hold cells together (like a clothing snap)

gap junction

formed by ring-like connexons, located in cardiac and smooth muscle, embryonic tissue, lens and cornea

different types of glands

endocrine, exocrine, unicellular

endocrine

no ducts, secrete hormones directly into blood

exocrine

maintain contact with epithelia surface via ducts, external or internal

unicellular

can be endocrine or exocrine, found in nonsecretory epithelia

classification of duct shape

simple (unbranched)

compound (branched)

classification of gland shape

tubular (narrow)

acinar (dilated sac)

tubuloacinar (both)

modes of glandular secretion

protein secretion

merocrine secretion

holocrine secretion

protein secretion

lipid droplet covered by membrane, used by mammary glands

merocrine secretion

uses vesicles that release via exocytosis, used by eccrine sweat glands (tear glands, pancreas, gastric glands)

holocrine secretion

cells accumulate a product until they disintegrate, done by oil glands of scalp and skin

types of body’s membranes

cutaneous membrane

mucous membrane

serous membrane

cutaneous membrane

* the skin
* largest membrane in the body
* contains stratified squamous epithelium (epidermis) resting on connective tissue (dermis)

mucous membrane

* lines passageways that open to external environment
* consist of epithelial, areolar and smooth muscle tissue
* absorption, secretion and protection

serous membrane

* internal membranes
* contain simple squamous epithelium and areolar tissue
* covers organs and lines walls of body cavities

modes of tissue growth

hyperplasia

hypertrophy

neoplasia

hyperplasia

cell multiplication

hypertrophy

enlargement of preexisting cells

neoplasia

development of a tumor

ways tissue can change from one type to another

differentiation

metaplasia

differentiation

development of more specialized form from unspecialized tissue

metaplasia

changing from one type of mature tissue to another

ways the body repairs damaged tissues

regeneration

fibrosis

regeneration

replacement with same cell type

fibrosis

replacement with scar tissue

histological structure of the epidermis

keratinized stratified squamous epithelium

* stem cells
* keratinocytes (majority)
* melanocytes
* tactile
* dendritic
* strata

histological structure of the dermis.

connective tissue

* mostly collagen
* papillary layer (areolar tissue)
* reticular layer (dense irregular tissue)

cyanosis

blueness due to oxygen deficiency

erythema

redness due to increased blood flow

pallor

paleness due to decreased blood flow

albinism

milky white skin and blue-gray eyes due to genetic lack of melanin synthesizing enzyme

jaundice

yellowing due to bilirubin in blood

hematoma

bruising (clotted blood under skin)

bronzing

excessively tan/brown. Symptom of Addison’s Disease

common markings of the skin

friction ridges

flexion lines

freckles and moles

hemangiomas

friction ridges

markings on the fingertips that leave oily fingerprints on surfaces we touch

flexion lines

creases on digits, palms, wrists, elbows

freckles and moles

aggregations of melanocytes

hemangiomas

birthmarks, caused by benign tumors of dermal capillaries

structure and function of nails

* nail plate, free edge, nail body, nail root
* function for grooming, picking apart food, counterforce to enhance sensitivity, etc

two types of sweat glands

apocrine and merocrine (eccrine)

apocrine sweat gland

* groin, anal region, axillam areola, beard area
* inactive until puberty
* responds to stress and sexual stimulation
* ducts lead to hair follicles
* bromhidrosis

merocrine (eccrine) sweat gland

* most numerous
* palms, soles, forehead
* simple tubular glad
* cools body

sebaceous glands

* flask-shaped, short ducts
* sebum- oily secretion
* keep skin and hair from becoming brittle and dry

ceruminous glands

* coiled, simple tubes
* external ear canal
* earwax (cerumen)
* waterproofs and protects ears

mammary glands

milk producing glands that develop only during pregnancy

modified apocrine sweat glands

rich secretion released through ducts opening at nipple

three most common forms of skin cancer

* basal cell carcinoma
* squamous cell carcinoma
* malignant melanoma

basal cell carcinoma

most common

least dangerous

forms from cells in stratum basale

squamous cell carcinoma

arises from keratinocytes of stratum spinosum

malignant melanoma

most dangerous

arises from melancytes

three classes of burns

first degree

second degree

third degree

first degree burn

epidermis only

heals in days

second degree burns

part of the dermis

2 weeks-several months to heal, may leave scars

third degree burns

all of epidermis/dermis + deeper tissue

needs fluid replacement

infection control

supplemental nutrition

tissues and organs that compose the skeletal system

* cartilage
* ligaments
* tendons

functions of the skeletal system

* support
* protection
* movement
* electrolyte balance
* acid-base balance
* blood formation

bones as a tissue vs as an organ.

tissue: osseous tissue (connective tissue with the matrix hardened by calcium phosphate and other minerals)

organ: consists of multiple tissues

osteogenic cell

stem cells found in endosteum and inner layer of periosteum

osteoblast

bone forming cells

osteocytes

strain sensors, regulate bone remodeling

osteoclast

bone-dissolving cells

importance of each constituent of bone tissue

* mineral portion gives stiffness
* protein/polymer portion gives flexibility

histology of the 2 types of bone tissue

compact bone tissue:

* concentric lamellae around central canal
* perforating (perpendicular) canals

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spongy bone tissue:

* trabeculae (thin plates of bone)
* spaces filled with red bone marrow
* few osteons
* no central canals

red bone marrow

(myeloid tissue)

makes blood

yellow bone marrow

stores energy(fatty tissue)