animal cells and tissues Flashcards
How are erythrocytes (red blood cells) specialised to carry out their job?
-flexible due to a well developed cytoskeleton so can twist and turn to travel through narrow capillaries
-large SA:V (increased by biconcave shape) so oxygen can diffuse across membranes easily and can reach all regions in the cell -> speeds up gas exchange
-no nucleus
What is the role of an erythrocyte?
to carry oxygen from the lungs to respiring cells
What organelles are lost at differentiation of erythrocytes?
no nucleus, mitochondria or endoplasmic reticulum and little cytoplasm
How are sperm cells specialised to carry out their job?
-specialised digestive enzyme called acrosome which digests the outer protective covering over the ovum to allow the sperm head to enter
-a tail strengthened by protein filaments which are manipulated by the cytoskeleton to move the tail and propel the sperm towards the ovum (spiral/coil-shaped movement of tail)
-small and thin so can move easily
-many mitochondria to carry out aerobic respiration- ATP provides energy for undulipodium (tail) to move
Squamous epithelial cells
-single layer of flattened, smooth cells for a short diffusion distance
-basement membrane is composed of collagen and glycoproteins secreted by epithelial cells that binds them to the connective tissue
-held in place by basement membrane
-e.g. in alveoli and some blood vessels
ciliated epithelial cell
-goblet cell produces mucus
-many cilia that beat in a synchronised pattern to move the mucus produced by the goblet cells
-columns shaped cells that cover many surfaces
-e.g. found in trachea, uterus, bronchi
What are the 4 main tissue types in the body?
epithelial
connective
muscle
nervous
epithelial tissue
-made up almost entirely of cells which are very close together and form continuous sheets
-no blood vessels- cells receive nutrients by diffusion from tissue fluid in the underlying connective tissue
-some have smooth surfaces but some have cilia or microvilli
-have short cell cycles and divide up to 2x or 3x a day to replace work or damaged tissue
-functions: protection, absorption, filtration, excretion and secretion
muscle tissue
-well vascularised- good supply of oxygen and other nutrients
-elongated and contain microfilaments made of up proteins actin and myosin -allows muscle contraction
-the connective tissue package skeletal muscles, joined to bones by tendons- allows bones to move during contraction
(smooth muscles found in walls of intestines, blood, vessels, uterus and urinary tracts- propels substances along these tracts)
(cardiac muscles make up the walls of the heart- allow the heart to contract and pump blood)
connective tissue
-consists of non-living extracellular matrix containing proteins (collagen and elastin) and polysaccharides (hyaluronic acid traps water) -separates living cells in tissue and enables it to withstand forces e.g. weight
e.g. bones, cartilage, tendons, ligaments, skin
-immature cells in cartilage are called chondroblasts and they secrete the matrix then mature into chondrocytes which maintain the matrix
fibrous cartilage
occurs in discs between the spine and the knee joint
elastic cartilage
makes up the outer ear (pinna) and the epiglottis (flap that closes over your larynx when you swallow)
hyaline cartilage
-forms embryonic skeleton
-covers ends of long bones in adults
-joins ribs to sternum
-found in the nose, trachea and larynx
What is the function of a neutrophil?
to ingest invading pathogens- bacteria and some fungi by phagocytosis
properties of neutrophils
-multilobed nucleus
-2x size of erythrocytes
-attracted to and travel toward infection sites by chemotaxis
