Cells and Tissues Flashcards
List the differences between prokaryotic and eukaryotic cells.
Eukaryotic cells contain membrane bound organelle
Eukaryotes have a nucleus
Eukaryotes tend to be larger
Prokaryotes cell wall made of peptidoglycan
List the organelles of a cell and explain the function of each.
CELL WALL - Gives shape and strength
CELL MEMBRANE - Semi-permiable, protects, guards cell
MITOCHONDRIA - Provides energy for the cell
NUCLEUS - Controls cell. Contains DNA
RIBOSOMES - Produces proteins
LYSOSOMES - Contain enzymes for digestion
GOLGI BODY - Processes and packages proteins
ROUGH ER - Houses ribosomes
SMOOTH ER - Transports materials through cell
Describe the role of the cell nucleus.
The main function of the cell nucleus is to control gene expression and mediate the replication of DNA during the cell cycle.
Define Mitosis and Meiosis.
MITOSIS
The process by which normal cells replicate. Produces 2 identical daughter cells.
MEIOSIS
The process by which gametes replicate. Produces 4 different gametes. Oogenesis or Spermatogenesis.
Draw a labeled diagram of a cell membrane and describe how its structure relates to function
Semi-permiable. Made of glycoproteins with hydrophobic tails and hydrophilic tails. Also contains proteins which allow sone transportation through the membrane e.g iron channels and pumps.
Describe the characteristics and function of epithelium.
PROTECTION - As a barrier between the outer world (or inner spaces) and our bodies.
SECRETION - When our bodies need to release material, like hormones into the blood, this tissue has to allow for such material to pass through. Often, it is the cells within the epithelial tissue that make the material for secretion.
ABSORPTION - Epithelial tissue facing our digestive tract has to be very good at absorbing nutrients from the digestive tract lumen in order for us to get what we need from what we eat.
EXCRETION - Epithelial tissue even lines the excretory lumina, like the tracts from the kidneys through to the urethra.
List and describe the different types of epithelium and suggest a location where each might be found.
SIMPLE - Single layered
STRATIFIED - Several layers
PSEUDOSTRATIFIED- Looks stratified but is actually simple
SQUAMOUS - Squashed cells (easy to diffuse through). Simple squamous found in alveoli and blood vessels. Stratified squamous found in the oral cavity, anus, vagina and skin.
CUBOIDAL - Cells that are equal in width and height. Simple cuboidal found in the salivary and lachrymal glands
COLUMNAR - Cells that are longer than they are tall. Lines most organs of the digestive tract.
Describe the general composition of connective tissue.
Connective tissue is made up of specialized cells and extracellular matrix composed of extracellular protein fibers and a ground substance
– Underlies epithelium, supports capillaries, small nerves
Categorise different types of connective tissue according to structure and function.
CONNECTIVE TISSUE
- Non-living material
- Living material e.g fibrinoblasts
- Structural/Metabolic Support
SPECIALISED CONNECTIVE TISSUE
-Consists of the Extracellular Matrix: Ground substance (Proteins, peptoglycans, water), tissue fluid, fibres (collagen, reticular, elastic)
Bone & cartliage, ligaments, adipocytes and blood.
Define homeostasis.
A tendency towards stability of the internal environment of a healthy organism
Comare and contrast negative and positive feedback control mechanisms.
NEGATIVE FEEDBACK
Response decreases the effect of the original stimulus
POSITIVE FEEDBACK
Response increases the effect of the original stimulus
List the components of a negative feedback mechanism.
Change in variable
Sensor
Integrating centre
Effector
List 5 physiological variables that are controlled by negative feedback.
Temperature - 37oc Blood glucose - 4.5-5.6mmol/L Blood volume - 60-80ml/Kg Blood Pressure - 120/80mmHg Electrolyte levels PaCO2 PaO2
Illustrate how body temperature is controlled by negative feedback.
Receptors in skin and brain -> Hypothalamus -> Blood vessels, sweat gland cells, skeletal muscle, hair follicles -> Change in body temp
Use a named example to illustrate positive feedback.
Blood clotting and child birth.
Head of foetus pushes against cervix -> Nerve impulses from cervix transmitted to brain -> Brain stimulates posterior pituitary gland to secrete oxytocin -> Oxytocin carried in bloodstream to uterus -> Oxytocin stimulates uterine contractions and pushes foetus towards cervix -> Head of foetus pushes against cervix.
