Human Anatomy 2500: Chapter 2: Cells
∙ Cytology or cell biology is the study of cells.
∙ They keep us in homeostasis.
∙ Compartmentalization is the isolation of specific kinds of chemicals in specific places.
∙ Cells have different functions:
a) Cover the body.
b) Align the organs.
c) They store materials.
d) They allow movement.
e) They are the connectors.
f) They are our bodies defence.
g) They communicate with each other.
h) They reproduce.
The three principle parts of a generalised cell are the plasma membrane, cytoplasm and the nucleus. We also discuss several other topics like Why you should believe the law of demand?
Plasma membrane: Structure, Function and Transport
Keeps all the materials inside, they are semi permeable and are the gatekeepers.
Picture a tub that has ducks and bubbles in it. The plasma membrane is the tub.
Transmembrane (Integral membrane): pass things from one side to the other. Peripheral (means on the outside): support the plasma membrane and have enzymes that start chemical reaction within the cell.
Carbohydrate (the image resembles the letter Y) If you want to learn more check out What are the classifications of the periodic table?
Glycolipid: a combination of carbohydrate and a lipid.
Glycoprotein: when a protein and carbohydrate combine.
Glycocalyx: When all the glycols and carbohydrates combine; this a glue for the cell; they help cells bond together when necessary; they contain cell identifiers.
Hyperplasia is out of control cell growth. This is caused by cells not identifying with each other therefore not communicating with the other to know what they are doing.
Receptor: Binds to ligand, specific, for cell recognition.
Transport across the plasma membrane:
a) Intracellular fluid (ICF): All fluids inside the cell (cytosol)
b) Extracellular fluid (ECF): All fluids outside of the cell (blood plasma) c) Interstitial fluid: the space between cells. Surrounds the cells and contains nutrients and oxygen for cells
d) Plasma: ECF in our blood.
e) Lymph: ECF in our lymphatic vessels.
Passive versus Active processes
Active uses ATP whilst passive kinetic energy.
Kinetic energy transport
Filtration: in the kidney We also discuss several other topics like What organization was the largest contributor to the first earth day?
Diffusion: higher concentration to lower
Osmosis: movement of water particles from a higher concentration to a lower concentration through a semi permeable membrane
Facilitated diffusion: integral proteins are used as transportation. Active transport
Vesicles move substances into and out of the cell.
Endocytosis – (three types): move substances in vesicles into the cell
Receptormediated endocytosis: there must be a receptor there to activate. This is how HIV enters our body.
Phagocytosis: pseudopods must be there (resembles the
computer/video game pacman)
Bulkphase endocytosis (pinocytosis): cell drinking
Exocytosis: cells moving out of the cell in vesicles
Transcytosis: combination of exocytosis and endocytosis.
This has two components, the cytosol and organelles.
∙ Cytosol: This is the water in the tub; the fluid part of the cytoplasm that surrounds the organelles.
The cytoskeleton is made up of microfilaments.
Microfilaments: used for locomotion and division. They are the smallest of the bunch and support the microvilli.
Intermediate filaments: Anchor the organelles inside the plasma membrane. Microtubule: Largest; Flagella and Cilia; the centrosome. This are found near the nucleus. We also discuss several other topics like What is the role of people and organizations?
∙ Organelles: specialized structures with the cell have specific shape and functions
Centrosome: Made up of 2 centrioles that are right angle to each other. They give rise to basal granules of cilia and flagella, and to produce spindle apparatus at the time of cell division. Each centriole has 9 peripheral groups of triplet microtubules, without any central microtubules. This is called 9+0 pattern. We also discuss several other topics like What is behavioral theory?
Cilia and flagella The flagella can move the entire cell. The only one known is the sperm cell.
Ribosomes site for biological protein synthesis
Clinical connection: Cilia and smoking
Smoking chars or obliterates the cilia within the trachea and the ability for the trachea to do anything.
1. Rough Endoplasmic Reticulum
Studded with ribosomes.
Continuous from the nuclear envelope.
Cistens the flat sacs in the plasma membrane; they move certain proteins
2. Smooth Endoplasmic Reticulum
Synthesises fatty acids.
Detoxifies certain drugs and steroids.
leave RER in a transport vesicle, enter Golgi apparatus at the entry, continues until it gets to a transport vesicle, continues and then chooses how it’s going to exit:
1) Secretory vesicle exocytosis 2) membrane vesiclemerge with plasma kept in the cell. 3) transport vesicle become a lysosome.
Lysosome contain very strong digestive enzymes that we need to digest our food. Clinical connection: TaySachs
Usually inherited; when the lysosomes are faulty/damaged or totally lacking. Organelles
Peroxisomes smaller than lysosomes. This detoxifies toxic substances such as alcohol; found in the liver.
Proteasomes destroy damaged/faulty proteins; found in the cytosol in the cell. We also discuss several other topics like What is performed to achieve behavior modification?
Parkinson’s disease Little to no control of your motor skills; tied to substana nagra a substance produced (the packaging isn’t happening)
Alzheimer’s disease protein build up in the brain and makes neuro fibrillary (place) builds and starts to affect memory.
∙ This is the powerhouse of the cell.
∙ Generate ATP.
∙ Needed for cellular respiration.
∙ Actively prevalent in metabolism.
Double wall membrane: external and internal.
Cristae is singular for cristernae.
Spherical or oval shaped.
Nuclear envelope consistent with the RER.
Mitotic apparatus made up of mitotic spindle and centrioles nuclear pore allows for things to move in and out of the cell.
Sample question: all cells have a nucleus. Ans: false: red blood cells don’t have a nucleus.
Malignant: out of control (harmful)
Geriatrics study of people as they get older and elderly who have limited capabilities.
Gerontology the scientific study of old age, the process of aging, and the problems of old people.