Stem cells and differeniation Flashcards
Enthrocytes
Flattened biconcave shape - increases SA:V ratio, maximising the oxygen absorption - quicK diffusion rate
No nuclei - more space for haemoglobin
Flexible - to fit through narrow capillaries
Neutrophils
Part of immune response
Multi lobed nucleus- for squeezing through small gaps to get to site of infection
Granular cytoplasm - Contains lysosomes that conrain enzymes used to attack pathogens
Sperm cell
Male gamete
Tail/ flagellum - capable of movement
Lots of mitachondria/ enzymes - supply energy to swim
Acrosome on head- digestive enzymes are released to digest protective layers around the ovum and allow spleen to penetrate - fertilisation
palisade
Found in mesophyll
- chloroplasts ABSORB large amounts for photosytnethsis
- cells CLOSELY slacked to form a continuous layer
THIN walls increase diffusion rate of CO2
Large vacuole to maintain turgor pressure
Chloroplasts move within cytoplasm in order to absorb more light
Root hair cells
Surfaces of roots near growing tips
- long hair liek extensions called Root hair cells which I crease the surface area of cell
This MAXIMISES uptake
Lots of mitachondria which provide more energy for active transport
GUARD cells
Form small opening called stomata
Needed for co2 to enter plants for photosynthesis
Loosing h20 causes them to become LESS swollen as a result of osmotic forces - change shape and stoma closes to prevent further loss
Cell wall - thicker on ONE side
Cell doesn’t change shape symmetrically as it’s volume changes
What is a tissue
A tissue is made of a collection of diffferentiated cells that have a specialised function/s
As a result each tissue is adapted for a particular function within the organism
4 main categories of tissues in animals
Nervous tissue
Epithelial tissue
Muscle tissue
Connective tissue
Nervous tissue
Adapted to support the transmission of electrical impulses
Epithelial tissue
Adapted to cover body surfaces, internal and external
Muscle tissue
Adapted to contract
Connective tissue
Adapted to either to hold other tissue together as as a transport system
Squamous epithelium
Made up of specialised squamous epithelial cells, sometimes lnown as a PAVEMENT epithelial due to flat appearance
Very THIN due to squat/ cells that make it up and only one cell thick
Present when rapid diffusion across a surface is essential
Forms lining of lungs and allows RAPID diffusion of oxygen into the blood
Ciliated epithelium
Made up of ciliated epithelial cells
Hair like structure called CILIA on one side - move in RHYMIC manner
Lines tranchea causes mucus to be swept away by the lungs
Goblet cells RELEASE mucus to trap unwanted particles present in the air , preventing particles which may be bacteria from reaching alveoli once inside the lungs
Microtubules - 9+2 arrangement
Fallopian tubes
Mobile or stationary e.g. sensory organs
Muscle
Needs to be able to contact in order to move bones which In turn move the different part of the body
Different types of muscle fibres
Smooth muscle
Inability to control their movement
HOLLOW organ e.g. uterus and stomach
Skeletal muscle
Attach to bones and have the main function of contracting to facilitate movement of our skeleton
Contain microtubules which contain contractile proteins
Cardiac muscle
High contractile strength
SOLELY in the walls of the heart
Similarities to skeletal muscles in that is stimulated and smooth muscles in that is contraction are NOT under contious control
Epidermis
Single layer of closely packed cells covering surfaces of plants
Covered by wa y cuticle( waterproof)to prevent loss of water
Stomata- formed by a pair of guard cells that open and close
Allow CO2, O2 and water vapour in and out
Short distance so light can penetrate - 1 cell thick, transparent
Protective barrier agianstpp
Xylem tissue
Type of vascular tissue responsible for the transport do water and minerals
Tissue is composed of vessel elements which are composed of vessel elements - ELONGATED dead cells
Walls of these cells are strengthened with a waterproof material called lignin, which provides structural supporT
NON living
Pits - allow water to leave xylem to get to shoots
Phloem
Type of vascular tissue
Responsible for transport of organic nutrients particularly sucrose from leaves and stems where it’s made
Composed of volume of sieve tube cels Seperated by perforated walls called sieve plates
Connected to companion cells - ATP for active transport
No nucleus - more space
Both directions
Parenchyma - store food and release chemicals do not eaten by herbivores
Organs
Collection of tissues that are adapted to perform a particular function in an organism
Organ systems
Large multicellular organisms have coordinated organ systems
Each organ system is composed of a number of Organs working together to carry out a major function in the body
What are stem cells
Able to undergo cell division again and again and are the source of new cells necessary for growth development and tissue repair
Once stem cells become specialised they loose the ability to divide entering the g 0 phase if the cell cycle
Activity do stem cells has to be strictly controlled
