Cell Function And Homeostasis Flashcards
What is the function of the nucleus
Largest organelle which is within all cells (minus rbcs) and it contains genetic material
What is the function of plasma membrane
Controls the passage of substances in and out of the cell regulating intracellular environment
What is the function of the ribosome
Synthesise protein from amino acids using RNA template
What is the function of mitochondria
Aerobic respiration with O2 and ATP ( which can be used to make energy)
What is the function of smooth endoplasmic reticulum
Synthesis lipids and steroids hormones
What is the function of rough endoplasmic reticulum
Studded with ribosomes which synthesis protein and leave by exocytosis
What is the function of the Golgi apparatus
Synthesised proteins are packaged and stored here
What is the function of lysosome
Small membranous vesicles containing enzymes
What is the function of chromatin
Helps compact DNA from longer strands into smaller packages as part of mitosis
What is the function of centrioles
Are responsible for producing cellular spindles in mitosis as well as making micro tubules
What are the three ways that substances can move through the cell membrane
Osmosis, diffusion and active transport
What is the definition of osmosis
Movement of water from and area of high concentration to an area of low concentration ( down a concentration gradient)
What is the definition of diffusion
Movement of molecules from an area of high concentration to an area to low concentration
What is the definition of active transport
Transport of substances up the concentration gradient requiring energy and carriers e.g Na/K pump
How many cell types are there
Approx 200 cell types
What are some examples of these cell types
Stem cells, erythrocytes , leukocytes, platelets, neurons, neuroglial cells, myocytes and chrondrocytes
What are the different types of cell actions
Reproduce, nourishment ( create and maintain), movement ( energy and transport) , excretion ( get rid of waste) , growth and respiration
What are examples of cells in action
Red blood cells - carry oxygen
Kidney tubule cells - controls water & salt excretion
Cardiac cells - contract & control heart pumping
Cartilage- structural support
Neurone - conduct electrical impulses
Sperm - convey genetic material for reproduction
What are the four different types of cellular tissue types
Connective tissue, epithelial tissue, muscle tissue and nervous tissue
What is connective tissue
Lattice shape, most abundant type of cells - binding, supporting, protecting ( e.g. cartilage , blood, adipose, bone)
What is epithelial tissue
Cells forming continuous sheets often lining body cavities ( e.g. skin, gut lining , glands )
What is muscle tissue
Skeletal muscle under voluntary control, attached to bone for motion/ posture
What is the two different types of muscle tissue
Smooth muscle and cardiac muscle
What is smooth muscle
Forming walls of tubes e.g. airways, blood vessels, gut, bladder, uterus for propulsion of substances
What is cardiac muscle
Under involuntary control causing the heart to pump
What is nervous tissue
Neurones conduct electrical impulses throughout the body ( e.g. brain, spinal cord ) to control body function/ movement
What is the order of organismal development
1) chemical level
2) cellular level
3) tissue level
4) organ level
5) system level
6) organismal level
What is apoptosis
Cell suicide and helps to avoid continuous replication as well as important to allow new cells to grow
What is necrosis
Cell damage/ disease
What are some cells that continually replaced
Gut epithelium ( turnover every 3 days ) and skin epidermis ( turnover every 2-4 weeks)
What are some cells that aren’t replaced
Muscle
Nervous system (50% of cells will die by the time we are old)
What occurs in aging
Mitosis lows down so cels that die aren’t replaced which causes signs of aging
How does apoptosis affect aging
Can increase in some cells causing disease e.g. Alzheimer’s where valuable nerve cells die more quickly
It can also stop which causes cells to ver divide causing tumors
What is homeostasis
When conditions in the internal environment are maintained within physiological limits
What occurs when homeostasis is disturbed
Illness may result, if body cells aren’t brought back death may occur
What must be kept constant to protect the cell
Chemical constitutions
Osmotic pressure
Temperature
O2/CO2 levels
How does homeostasis work
Receptors
Having a control system
Effectors
How is high body temperature controlled
Receptors = skin& hypothalamus receptors
Control system= hypothalamus & pituitary glands
Effector= sweating & skin capillary vasodilation
Corrective response = heat loss
How is low body temperature controlled
Receptors = skin & hypothalamus
Control system = hypothalamus & pituitary gland
Effector= skin hairs stand on end, skin capillary vasoconstriction, shivering
Corrective response = heat gain
What is negative feedback
If response reverses original stimulus ( goes back to normal levels)
What is positive feedback
If response enhances original stimulus ( continues to reinforce the original stimulus)
