B.2.3 Cell specialization

Based on the 3rd edition biology textbook written by C.J. Clegg, Andrew Davis, Christopher Talbot

zygote

cell produced by the fusion of gametes

embryo

an organism in the earliest stages of growth when its basic structures are being formed

morphogen

a molecule present in a concentration gradient that specifies the fate of each cell along the gradient

embryonic stem

undifferentiated cell in early-stage embryo capable of continual cell division and of developing into all the cell types of an adult organism

stem cell

undifferentiated cell in embryo or adult that can undergo unlimited division and can give rise to one of many different cell types

stem cell niche

specific microenvironment in the body that either maintains the stem cells or promotes their proliferation and differentiation

ex: bone marrow » blood cell formation, osteoblasts (bone cells) & haematopoietic stem cells (HSCs) help form red and white blood cells and platelets

hair follicles » bulge hair follicle stem cells, can increase rapidly with length

totipotent

capable of giving rise to any cell type in an organism, including making more totipotent stem cells and making the cells that become the placenta

pluripotent

able to develop into many different types of cells or tissues in the body except becoming placental cells or totipotent stem cells

multipotent

can create maintain and repair the cells of one particular organ or tissue

egg/ovum

a female gamete

has necessary nutrients for the early development of the fertilized egg

sperm

motile male gamete

only made of a nucleus, mitochondria, and flagellum to help move to the egg

red blood cell

large surface area to help diffuse oxygen, small to fit through lumen of capillarities

white blood cells

when foreign matter enters the body, the cells attack and destroy it, big and few in numbers, engulf or digest pathogens

neurons

transmit electrochemical impulses through the body allowing coordination and response to stimuli to occur

striated muscle fibres

multinucleated cells that attach to muscles to allow movement, help with coordinate contraction and muscle force generation

alveolus

air sac in the lungs

pneumocyte

specialized cells that occur in the alveoli of the lungs

epithelium

sheet of cells bound strongly together, covering internal or external surfaces of multicellular organisms

surfactant

a detergent secreted by cells in the wall of alveoli which breaks surface tension and stops alveoli walls from sticking together keeping the alveoli open.

myogenic

originating in heart muscle cells themselves, as in the generation of the heartbeat

myofibril

contractile protein filament from which muscle is composed

striated

muscle tissue that is marked by alternating dark and light bands

sacrolemma

membranous sheath around a muscle fibre.

intercalated discs

link cardiac cells together and define their borders, and facilitate cell-to-cell communication, which is needed for coordinated muscle contraction

tendon

fibrous connective tissue connecting a muscle to bone

oocyte

a female sex cell in the process of a meiotic division to become an ovum