cell diversity and cell differentiation - organ & organ system/tissues/stem cells

Question 1

define tissue + examples

Answer 1

group of cells that work together to perform a specific function
e.g. muscle, epithelial, blood, glandular

Question 2

define organs + examples

Answer 2

collection of tissue working together to perform a function/functions
e.g. kidney, liver, small intestines

Question 3

define organ system +examples

Answer 3

a number of organs working together to carry out an overall life function
e.g. digestive, respiratory, cadiovascular, nervous, immune

Question 4

muscle tissue: structure and functions

Answer 4

elongated and contain special organelles called myofilament(made of proteins actin and myosin) allow tissue to contract.
Function: allow movement
-Skeletal muscle: packaged by connective tissue, joined by bone and tendon. Muscle comtract, causes bone to move
-Cardiac muscle: makes up wall of heart and allows heart to beat and pump blood
-Smoooth muscle: in walls of intestines, blood vessels , uterus and urinary tracts - propels subsatnces along tracts

Question 5

cartilage :structure and function

Answer 5

immature cells in cartilage (chondroblasts) - they divide by mitosis & secrete extracellular matrix - becomes synthesised = mature and less active
TYPE OF CARTILAGE:
-Hyaline: froms the embryonic skeleton, covers ends of long bones. Found in nose and trachea (as C-rings)
-Fibrous: in disc between vertebrae in backbone and in knee joints
-Elastic : makes up pinna (outer ear) adn epiglottis (flap that closes the larynx when you swallow)

Question 6

function of Xylem

Answer 6

carry water and minerals from roots to all parts of the plant
it is a vascular tissue in plants

Question 7

function of phloem

Answer 7

sieve tubes thta transfer the products of photosynthesis (mainly sucrose sugar), in solution, from leaves to parts of the plant that don’t photosynthesise, like roots, flowers and growing shoots
vascular tissue in plants

Question 8

function of squamous epithelial

Answer 8

allow selective diffusion of material to pass through - short diffusion

Question 9

function of ciliated epithelial tissue

Answer 9

moving particles or fluid over the epithelial surface

Question 10

what are stem cells?

Answer 10

a cell that can divide (mitosis) an unlimited number of times
undifferentiated cells (that can differentiate into specialised cells, for growth and repair tissue)

Question 11

define potency

Answer 11

this ability of stem cells to differentiate into more specialised cell types

Question 12

what are the 3 types of potency and define them?

Answer 12

TOTIPOTENCY: totipotency stem cells that cna differentiate inot any cell type found in an embryo, as well as extra-embyonic cells (the cells that make up the placenta). The zygote formed when a sperm cell fertilises an egg cell in totipotent.
PLURIPOTENCY: pluripotency stem cells are embryonic stem cells thta cna differentiate into any cell type in the embryo, but not able to differentiate in extra-embryonic cells. Turn into any type of cell.
MULTIPOTENCY: multipotency stem cells are adult stem cells that have lost some of the potency associated with embryonic stem cells and are no longer pluripotent. Myeloid cells differentiate into red blood cells, platelets, white bood cells.

Question 13

where do you find stem cells?

Answer 13

embryonic stem cells - present in an early embryo formed when the zygote begins to divide
stem cells are also found in umbilical cord blood
adult stem cells- formed in developed tissue (blood, brain, muscle, bone marrow, adipose tissue (fat storage) and skin)
induced pluripotent stem cells (iPS cells) - developed in labs by reprogramming differentiated cells - switch on certian genes, to become undifferentiated

Question 14

what are the potential uses in research and medicine?

Answer 14

Bone marrow transplant- to treat diseases of blood (e.g sickle cell anaemia and leukaemia) and immune system (e.g. severe combined immunodeficiency/SCID), also treatment for specific cancers
Drug research- if stem cells can be made into particular human tissue,then new drugs can be tested first on these tissue (rather than animal tissue)
Developmental Biology- scientists can make use of stem cells to research and enable better understanding of multicellular organisms development. Can study how cell develop to make particular cell types and learns frunctions and what happens when they’re diseased. trying to find how embryos extend the capacity for growth and tissue repair, into later life

Question 15

what are erythrocytes?

Answer 15

they are red blood cells
-lacks a nucleus , cannot divide
-transportation of oxygen

Question 16

what are neutrophils?

Answer 16

they are white blood cells
-collect around foreign bodies (e.g. pathogens)
-destroy them by engulfing them (phagocytosis)

Question 17

what is the plant stem cell that differentiates into either xylem or phloem?

Answer 17

cambium