Lab 1

Question 1

What are the four primary tissue types?

Answer 1

epithelial: covers body surfaces, lines hollow organs, ventral cavities and ducts and form glands
connective: protects and support body and organs, bind organs together and store energy, provides immunity
muscle: movement and generating force
nervous: carries info
quickly from one side to the other

Question 2

What are the two types of epithelia?

Answer 2

covering and lining epithelia

• outer layer of skin
• inner surface of digestive and respiratory cavities
• inner surface of heart and blood vessel
• walls and organs of closed ventral body cavities
• ducts of exocrine glands

glandular epithelia
- most glands in the body

Question 3

What is the main characteristics of epithelia?

Answer 3

made of many cells close to each other (very little ECM)
have special types of junctional specializations
all have one free surface: apical (except endocrine glands) exposed to the lumen [body cavity/space], duct, tube or vessel
rests on a basal surface (basement membrane)
not vascularized = no blood vessels within epithelial layer
frequent divisions since exposed to wear and tear, injury needing replacement

Question 4

What are the functions?

Answer 4

covering epithelia:

• protect underlying tissues from physical damage
• allow and regulate passage of materials
• specialized epithelia form sensory parts of organs like eye, taste buds, ear , mouth

glandular epithelia
- classified as endocrine (hormones secreted directly into blood) or exocrine (release products onto free surface or open cavities)

Question 5

Classification of covering and lining epithelia?

Answer 5

• number of cell layers
  one layer: simple
  several: stratified

-shape of cells
flat: squamous
square: cuboidal
rectangular: columnar
if changes shape: transitional epithelium

-specialization of cell surfaces
microvilli
cilia

on microscope:
nuclei is flat and parallel = squamous
nuclei oval and parallel to axis on cell = columnar
nuclei is round and in the centre of cell = cuboidal

Question 6

What are 2 subtypes of epithelia?

Answer 6

simple
one layer
found in areas of minim wear and tear
main function: allow passage of substances between the lumen and tissues

stratified
many layers
thick
main function: to protect tissues they cover

Question 7

What is simple squamous?

Answer 7

one layer, flat cells
alveoli of lungs, glomeruli of kidneys and lining of heart, blood vessels and lymphatic vessels and ventral body cavities

thinnest = well adapted for diffusion, filtration and secretion

Question 8

What is simple cuboidal epithelium for?

Answer 8

one layer of cuboidal cells (round centred nucleus)
found in small glands, kidney tubules and ovary surface
for secretion, absorption

Question 9

What is simple columnar epithelium for?

Answer 9

one layer of columnar cells with oval nucleus
can be ciliated (contain microvilli on apical surface of cells to increase surface area)=have cilia on apical surface, found in small bronchi, uterine tubes and part of the uterus, involved in secretion of mucus and other substances to move mucus or female reproductive cells) or non ciliated = mainly lining digestive tract

Question 10

What is simple pseudo stratified epithelium for?

Answer 10

one layer of many cells, rests on basal membrane
appears stratified
can be (non) ciliated (both)
ciliated= in trachea, primary bronchi, most upper respiratory tract and secretion and propulsion of mucus
non ciliated = lining of male urethra and ducts of large glands

Question 11

What is stratified squamous for?

Answer 11

several layers of squamous cells
thickest of all
function: protection
may or may not have keratin, touch protective protein that prevents water loss = resistant to friction and repels bacteria
keratinized: forms epidermis of skin
non-keratinized: lines wet surfaces like lining of mouth, esophagus, tongue, epiglotis, vagina

Question 12

What is stratified cuboidal epithelium for?

Answer 12

several layers of cuboidal cellsfound: largest ducts of sweat glands, mammary glands, salivary glands and male urethra
protection!!

Question 13

What is stratified columnar epithelium for?

Answer 13

several layers of columnar cells
very rare: lines urethra, large ducts and some parts of the eye
protection and secretion!

Question 14

Stratified transitional epithelium?

Answer 14

several layers
lines surfaces of organs subject to stretch, like bladder, ureters, parts of urethra
allows distension of urinary organs

Question 15

What is the main difference between endocrine glands and exocrine glands?

Answer 15

endocrine: secrete hormones, circulate through the body to target areas, act as chemical messengers
most are epithelial derivatives: by invagination from an epithelial sheet and initially have ducts connecting them to free surface of the epithelial sheet

exocrine: release products into free surface or open cavities like digestive, respiratory, reproductive, products are NOT released into blood

Question 16

What is the most abundant primary tissues?

Answer 16

connective tissue

Question 17

What is a main characteristic of CT?

Answer 17

abundant cells in ECM, embedded in ground substances

Question 18

What is the function of CT?

Answer 18

binding, support and packaging: form capsules around organs and form ligaments, tendons to which bone binds to each other or muscles, form 3D mesh fibres to support cells in large organs like liver and spleen
bone and cartilage support body organs

protection, defense and repair: great regenerative ability important for injury
scar tissue is formed of connective tissue which fill space of original tissue that does not regenerate
defense mechanisms: inflammation
skull is chamber that protects the brain

insulation: fat cells or adipose tissues cushions and insulates and provide energy as fuel
transportation: blood is CT and carries and delivers oxygen and nutrients to tissues

Question 19

What is the main four classification of CT?

Answer 19

blood, bone, cartilage and CT proper

Question 20

What are the three critera of division?

Answer 20

1. secrete matric or maintain it
   blast: undifferentiated cell type: division and secretes matric
   cyst: once matrix is produced: capacity for cell division lost and become mature cells, less active, maintain matric in healthy state

fibroblast: primary blast cells of CT proper
hemocytoblasts: primary blast cells of blood

chrondroblasts and osteoblasts: primary blast cells of cartilage and bone

accessory cells supported by CT
fat storing cells - energy reserve fuel
WBC, mast cells, macrophages, antibody producing plasma cells: mobile and migrate CT matrix into bloodstream, involved in body defence and elimination of dead or dying cells

2. fibres: provide strength ( 3 types)
   - collagen: white fibers, extremely tough, stronger than steel, high tensile strength, resist longitudinal stress
   - elastic fibres: yellow fibres, stretched 1.5 times their length, recoil to initial length, greater elasticity needed in lungs and blood vessels
   - reticular fibers: fine collagenous, delicate branching network support soft organs like liver and spleen
3. ground substance or ECM: amorphous susbtance that fills space between cells and contains fibres, composed of interstitial fluid, cell adhesion proteins (allow CT to attach themselves to matrix) and proteoglycans (proteins attached to polysaccharides = can trap more or less water depending on nature and form substance that can be fluid or semi stiff hydrated gel) = determine the properties of matrix
   eg. more polysaccharide = stiffer ground substance

ground substance supports cells and binds them together an funtion as a medium which nutrients and other things diffuse between capillaries and cells

Question 21

What is the extracellular matrix composed of?

Answer 21

fibers and ground substance

Question 22

Differentiate between the different tissues. (4)

Answer 22

epithelial: one or more layers, covers, protect, lines and moves, glandular activity
connective: sparsely arranged surrounded by a lot of ECM, supports body structures and transport

Muscle: long fibre like cells, can be branched and produces body movement

nervous: mix of many types of cells including neurons, communication

Question 23

What are muscle tissues?

Answer 23

specialized cells for force generation and contraction, cells are elongated and can change shape to become shorter or thicker

contracting: muscle cells pull at attached ends and cause body parts to move

Question 24

What is common to all muscle tissues?

Answer 24

made of many cells close together (little ECM)
well vascularized
elongated
contain myofilaments (contractile proteins)

Question 25

What are the three kinds of muscle tissue?

Answer 25

skeletal: long, rod like, striated, multinucleated, some skeletal muscles attach and cover the bony skeleton other attach to the skin like facial muscles

generate heat when they contract so maintain constant body temperature

Cardiac muscle: intercalated disks only in cardiac=anchor desmosomes and gap junctions, long cylindrical, striated, shorter than skeletal
elongated, branched and striated, one nucleus sometimes two, found in heart only
contraction: squeezes blood out of heart and propels into blood vessels

Smooth muscle: spindle shaped, one nucleus, not striated
found in walls of hollow organs and generally propel substances through these organs by alternating contraction and relaxation

Question 26

What are the functions of the nervous system?

Answer 26

constantly monitors changes inside and outside body
processes and interprets information, makes decisions about what should be done
carries order of what should be done to muscles and glands

Question 27

What are histological characteristics of nervous tissue?

Answer 27

made of many packed closely cells (little ECM)

most cells are strongly branched

Question 28

What are the two main groups of cells?

Answer 28

neurons: respond to stimuli, conduct electrical impulse to and from all body organs within CNS, have a cell body (with nuclei and organelles), dendrites that receive stimuli and axon that generate impulses and transmit from one part to another

glial cells: support, protect and bind neuron

Question 29

Where do we find nervous tissue?

Answer 29

the brain, spinal cord, nerves and associated ganglia