Principles of Human Anatomy: Unit 1 - Cytology

Cells

the most basic structural and functional unit of the human body

What biomolecules make up a cell?

nucleic acids, proteins, lipids, carbohydrates

Plasma membrane

divides the intracellular matrix from the extracellular matrix and controls what goes in and out of cell

made up of a lipid bilayer (phospholipids) and proteins

bilayer

hydrophilic, polar heads and hydrophobic non polar tails

peripheral protein

A protein embedded on surface of a membrane -> either on intracellular matrix side or extracellular matrix side (not both)

Glycolipid

Carb/sugar attached to a lipid (part of phospholipid)

glycoprotein

carb attached to a protein

transmembrane protein

spans the entire membrane, touching the ECM and ICM

channel protein

a protein that is always open and allows any solute molecule to pass into and out of the cell

cholesterol

regulates membrane fluidity

Glycoprotein

sugar attached to protein (on protein)

Glycocalyx

The external, sugary surface of a plasma membrane that is important for cell-to-cell communication, allowing cells to recognize other cells and decide if other cells are friends or pho

• made of glycolipids and glycoproteins

receptor protein function

binds to chemical messengers such as hormones sent by other cells

enzyme protein function

breaks down a chemical messenger and terminates its effect on the target cell

gated channel protein function

channel that opens and closes to allow solutes through only at certain times

cell-identity marker protein function

a glycoprotein acting as a cell-identity marker distinguishing the body's own cells from foreign cells

cell-adhesion molecule

a CAM protein in membrane that binds one cell to another

intracellular matrix (ICM) consists of

cytoplasm (organelles and cytosol)

extracellular matrix

space between cells consisting of fibrous and non-fibrous proteins, organic molecules, and fluid

nucleus

control center of the cell, contains instructions for cell tasks, houses DNA

Golgi apparatus

sorts and packages proteins into vesicles to be delivered in and out of the cell (post office)

centriole

organelle that aids in cell division

ribosomes

produce proteins, some float in the cytoplasm, others attach to rough ER

Rough Endoplasmic Reticulum

Makes proteins, folds them, and checks their quality. Also functions in transport of proteins within the cytoplasm

Smooth ER

makes lipids and chemically detoxifies

lysosome

An organelle containing digestive enzymes that eat old organelles and cell waste

cytoskeleton

network of fibers that make up the framework of the cell, it helps regulate cell shape

mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

Hemidesmosome

attaches cell to basement membrane

desmosome

attaches cell to cell and provides elasticity

tight junction

attaches cell to cell and prevents paracellular diffusion (nothing gets through)

gap junction

attaches cell to cell and establishes a pathway for rapid communication

cell differentation

the development of a more specialized form and function of cell (no cells are the same shape/size or have the same function) NOT COMPOSITE

cell differentation determined by

gene expression (found in nucleus)... different genes are "turned on"

histone

protein that DNA strands wrap around to fit in nucleus

• nucleosome (DNA wrapped around a histone)

gene

A segment of DNA on a chromosome that provides instructions for making a specific protein... controls characteristics and function of cells

protein production

transcription (occurs in nucleus), translation (occurs on ribosomes), and exocytosis (out of cell)

transcription

the organic process whereby the DNA sequence in a gene is copied into mRNA and leaves nucleus via nuclear pores (occurs in nucleus)

translation

the process whereby genetic information coded in messenger RNA directs the formation of a specific protein (occurs in a ribosome in the cytoplasm)

exocytosis

process of secretion from the cell through a vesicle

fates of proteins

1. packaged into lysosome as an enzyme

2. incorporated into plasma membrane as a membrane protein

3. exported out of cell by exocytosis to run through blood stream and fine receptor to elicit response in body

cellular permeability

how easy it is for substance to move across cell membrane

filtration

relies on pressure (particles move from high to low)

simple diffusion

move from high to low solute concentration

facilitated diffusion

substance/particle binds on one end of protein causing a change in configuration to channel

active transport

particles move against concentration gradient using ATP and protein pumps

metabolism

what a cell does

• catabolic- break down particles

• anabolic- build up products

Interphase

Where a cell spends most of its life

• G1- growth, normal processes

  • G1 checkpoint- checks cell size and determines if it’s healthy for division

• S Phase- DNA replication

• G2- more growth, cells function

  • G2 checkpoint- ensures DNA was properly replicated

• G0- cell leaves cell cycle to differentiate

Prophase

chromosomes condense, nuclear envelope breaks down, spindle fibers grow from centrioles, centrioles migrate to opposite poles

Metaphase

chromosomes align in middle of cell

m checkpoint

checking to make sure cell is properly aligned in center of cell and ready to divide

Anaphase

spindle fibers pull apart sister chromatids

Telophase

chromosomes settle in opposite poles and decondense, nuclear envelope reappears

cytokinesis

division of cytoplasm and organelles

meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

uncontrolled cell division

start and stop signals fail resulting in improper cell division and a neoplasm

benign= mass of cells that stays in one place (non cancerous)

malignant= moves and spreads (metastatic) (cancerous)