mitosis & tissues Flashcards
what happens during interphase in the cell cycle?
- cell grows
- DNA is copied
- protein, lipid and carbohydrate synthesis occur
- centriole replication occurs
ATP is made and used
what happens during the mitotic phase in the cell cycle?
- cytoplasm divides
- nucleus divides
why do cells undergo mitosis?
- as we grow, cells become bigger and then get to a stage where they become to large for the cell membrane transport process
- when they get to big the cells no longer function effectively
- when they get to big the cell will undergo mitosis to form two smaller daughter cells
what are labile cells?
cells that are constantly undergoing mitosis
what are stable cells?
they undergo mitosis only when some external factor indicates that they should do so
what are permanent cells?
they are amitotic - they lose the ability to undergo mitosis after a person is born
what does DNA stand for?
deoxyribonucleic acid
what does nucleotides consist of?
phosphate, deoxyribose sugar and a base
what are the sides of the DNA ladder formed by?
phosphate and deoxyribose
what bases project into the middle of the DNA ladder?
- Adenine (A)
- Thymine (T)
- Guanine (G)
- Cytosine (C)
what is cytokinesis?
splitting of the cytoplasm
what happens during prophase?
- nuclear membrane breakdown
- chromosomes form
- mitotic spindles form
what happens during metaphase?
- chromosomes line up along the middle of the cell
- mitotic spindle attaches to centromeres
what happens during anaphase?
- centromeres split and chromatids are pulled apart
- single chromosomes are pulled to either end of the cell
what happens during telophase?
- nuclear membrane forms
- mitotic spindle breaks down
- chromosomes unravel to form loose chromatin
what is a zygote?
when a male sec cell and a female sex cell join together
what must the zygote have to develop normally?
it must have 23 pairs of chromosomes = 46 in total
what is it called when a cell contains two copies of every chromosome?
diploid
what is meiosis?
a type of cell division that only occurs in the gonades
what is the definition of epithelial tissue?
a sheet of cells that covers a body surface, lines a body cavity or forms glands
what is the definition of connective tissue?
binds, supports, protects, insulates and/or transports substances within the body
what is definition of muscle tissue?
contracts to create movement of the whole body, skin or of substances within the body
what is the definition of nervous tissue?
create and transmits electrical signals allowing communication within the body
epithelia are innervated and avascular - this means what?
that they are supplied by nerve fibres, but do not contain blood vessels
what is simple squamous epithelium?
a single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm
what is the function of simple squamous epithelium?
- it allows materials to pass by diffusion and filtration in sites where protection is not important
- secretes lubricating substances in serosae (linings of ventral body cavity)
where is simple squamous epithelium found?
- kidney glomeruli
- air sacs of lungs
- lining of the heart
- blood vessels
- lymphatic vessels
what is simple cuboidal epithelium?
single layer of tubelike cells with large, spherical central nuclei
what is the function of simple cuboidal epithelium?
secretion and absorption
where is simple cuboidal epithelium found?
- kidney tubules
- ducts
- secretory portions of small glands
- ovary surface
what is simple columnar epithelium?
single layer of tall cells with round oval nuclei
what is the function of simple columnar epithelium?
- absorption
- secretion of mucus, enzymes and other substances
where is simple columnar epithelium found?
- digestive tract
- gallbladder
- excretory ducts of some glands
- uterus
what is stratified squamous epithelium?
thick epithelium composed of serval cell layers
what is the function of stratified squamous epithelium?
protects underlying tissues in areas subjected to abrasion
where is stratified squamous epithelium found?
- lining of the oesophagus
- mouth
- vagina
what describes pseudostraified columnar epithelium?
- formed by a single layer of cells of differing height
- free surface can have Cilla
- lines the respiratory and male reproductive tracts
- secretes mucus
what describes transitional epithelium?
- cells change shape as organ fills
- formed by more than one layer of cells
- lines the bladder and ureters
- prevents large increases of internal pressure as the organ fills
what is glandular epithelium?
cells that are specialised to make and secrete a specific product
describe exocrine gland
- secretes its product through a duct onto a body surface or into a body cavity
- example: a mucus secreting cell in the lining of the respiratory tract
- example: mammary glands secrete milk via the nipple
describe endocrine gland
- secretes its product directly into the blood
- example: a cell in the stomach wall that secretes gastrin into the blood that controls digestive system function
- example: the thyroid gland secretes thyroid hormone into the blood
what are the fibres in connective tissue?
- elastin
- collagen
- reticular
what is the consistency of extracellular matrix?
- liquid - like the plasma in blood
- soft - like in adipose tissue
- firm but flexible - as in cartilage
- hard - as in bone
what are some types of connective tissue?
- blood
- loose connective tissue
- dense connective tissue
- cartilage
- bone
what is blood made up of
- cells
- fibres
- matrix
what is areolar connective tissue?
it is loose connective tissue with a gel like matrix that wraps and cushions organs and holds a large volume of tissue fluid. located under epithelia
where can areolar connective tissue and adipose tissue be found in the body?
- under your skin
- around the kidneys
- eyeballs
- abdomen
- breasts
what does reticular connective tissue do?
it contains a network of reticular fibres that form a soft internal skeleton inside organs such as lymph nodes and spleen
what are dense connective tissue made up of?
fibres
describe dense regular connective tissue
- forms tendons and ligaments
- withstands strong pulling forces in one direction only
- mainly parallel collagen fibres
describe dense irregular connective tissue
- resists pulling forces from several directions
- located in joint capsules, skin dermis and digestive tracts
- mainly irregularly arranged collagen fibres
descrive elastic connective tissue
- allows tissue to recoil after being stretched
- parallel collagen fibres with large number of elastic fibres
- located in the walls of large arteries, vertebral ligaments and in large airways
describe elastic cartilage
- contains elastic fibres in matrix
- creates shape with flexibility
- located in ear and epiglottis
describe fibrocartilage
- contains thick collagen fibres
- located in intervertebral disc, pubic symphysis and knee joint
- strong and resists compression
describe hyaline cartilage
- supports, reinforces, acts as a cushion
- forms the skeleton in embryos
- covers the end of long bones
- joins the ribs to the sternum
- creates the shape of the nose, trachea and larynx
what are the 3 types of muscle tissue?
- skeletal
- cardiac
- smooth
describe cardiac muscle
- branched muscle cells
- located in the heart
- propels blood through blood vessels
- striated
- usually uninucleate
- involuntary
describe skeletal muscle
- attached to bone and skin
- creates facial expressions
- long parallel muscle fibres
- moves the body
- multinucleate
- striated
- voluntary
describe smooth muscle
- found in the walls of hollow organs
- not striated
- propels substances through body passages
- spindle shaped cells
- uninucleate
- involuntary
what does nervous tissue consist of?
- your brain, spinal cord and nerves
what do neurons do?
they are nervous tissue cells that create and transmit electricity
what does Glial cells (neuroglia) do?
it supports the neurons
describe membranes
- they cover the body surface and line body cavities
- they are formed by a continuous sheet of epithelial cells supported by a layer of connective tissue
describe cutaneous membrane
keratinised membrane that covers the outside of the body
describe mucous membranes/mucosae
wet membrane that lines body cavities open to the outside of the body
describe serous membranes/serosae
wet membranes that line body cavities that are not open to the outside of the body
