Anatomy of Cells Chapter 3
The cell - • Basic unit of life • 100 trillion in the human body • Variances – size, shape, function, ability to reproduce
Size • Micrometers • RBC – 7.5 micrometers • Ova – 150 micrometers • A period mark in the text represents 100 micrometers.
Appearance • Varies • Function • Area of body
This is done by the examination of the body at autopsy, of tissues removed during surgery, and by analysis of fluids from the body, such as blood or urine, in the clinical pathology laboratory".
"The forensic pathologist's involvement and investigation includes visiting the scene of death. Gathering information about what happened at the time and place of the subject's death, what he or she was doing, and the health of the subject is of vital importance. The forensic examination of the body includes examining the clothing on the body, the body itself, and the internal examination of the organs in the body, which is the autopsy. The autopsy may include microscopic and x-ray examinations of the tissues of the body". The forensic pathologist may call in many others in his search for answers.
Evidence such as fingernail clippings and scrapings in an assault case, swabs for examination for sperm and seminal fluid, hair samples, and fibers on the deceased's clothing and body are sent to a crime laboratory for a criminalist to study. Other evidence such as blood, urine, stomach contents, bile liver, kidney, lungs, brains, nail clippings, and hair are sent to a toxicologist. The Forensic scientist must "determine which injuries were received when the victim was alive (antemortem injuries), which changes occurred after death (decomposition), and which injuries were received after death (postmortem injuries).
Main structures of a “Typical” cell: • Plasma membrane • Cytoplasm – cell substance – cytosol – intracellular fluid • Nucleus
Cell membranes • Variety with variable capabilities • Plasma – sacs, canals – • Thin – 75 angstroms • Composed of lipid, protein, other molecules • Pg. 76 – fluid mosaic model – sheet-like made of fluid for mobility • Chemical bonds hold these molecules together • Selective permeability
Cytoplasm and organelles • Cytoplasm – cytosol and hundreds of organelles – creates a thickening effect • Water + starch • Many /most organelles not identified • Membranous/non-membranous organelles
Endoplasmic reticulum • Endoplasm –cytoplasm toward center of cell • Reticulum – network/wiring • Rows of canals and flat curving sacs throughout cytoplasm • Miniature circulatory system? • Rough – outer surface – ribosomes attached to synthesize proteins • Smooth – synthesize carbs and lipids • Thought to be a transport system
Ribosomes • Thousands in each cell • Some attached to ER – some free • Non-membranous • Two pieces – lg./sm. • Each piece has ribonucleic acid + protein • Ribosomal RNA – rRNA – translates genetic code • Messenger RNA – mRNA – copies DNA code • Transfer RNA – tRNA – places order • Ribosomes make protein
Golgi bodies • Near nucleus • Processes, packages, and transports protein • What is the importance of protein in the body?
lysosomes • Change in size/shape – age thing! • Infancy – tiny • Teen – little larger • Can destroy/digest cells with enzyme production • Leukocytes perform this action
Peroxisomes • Another sac of enzymes • Toxin busters • Kidney/liver commonly
Mitochondria • Two membranes • Inner membrane – adenosine triphosphate ATP • Oxidation reactions occur to produce energy • Power plants of the cell • The busier a cell is – the more mitochondria it contains
Nucleus • Largest of all cell structures • Central location • Contains DNA molecules • Thread-like (chromatin) • Before division DNA coils = break into rods called chromosomes (46) • Nucleus carries code for protein and enzymes for a cell • Nucleolus – inside nucleus – contain rRNA – decides when to divide
Cytoskeleton • Rod-like pieces for support • Muscle-like fibers for movement • Cell fibers look like web-like structure for support
Centrosome • Regulates build up and break down of fibers • Microtubule fibers in a spindle moves chromosomes before cell division • Centrioles – two – right angle to each other before division • Baby centriole is created prior to division
Cell extensions • Project from cell • Flagella, cilia, microvilli • Microvilli – epithelial – hundreds of hairs! Line intestines • Flagella/cilia – differ in size and number • Cilia – shorter, numerous – respiratory sys. • Flagella – longer, single - sperm
Cell connections (glue) • Matrix – connected to outside of cell • Integrins – glue to hold in place • Desosomes – spot welds • Gap junctions – channels form glue-heart • Tight junctions – collars hold together cells – intestines • See pg 87 for diagram
Chapter 3 review • Test next class
Article review Why is protein important?