A&P 1 Cytology

Cytoplasm

the substance that surrounds organelles and is located between between the nucleus and the plasma membrane.

Organelles

permanent structures with characteristic morphology, specialized for specific cellular activities

Inclusions

secretions and storage products of cells

Hypertrophy

increase in the size of cells without division the opposite of this is atrophy. Muscles increase in size by hypertrophy (not by making new muscles cells)

Hyperplasia

increase in the number of cells due to an increase in cell division

Cancer

also known as a malignant tumor or malignant neoplasm, is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. Not all tumors are cancerous; benign tumors do not spread to other parts of the body. Possible signs and symptoms include: a new lump, abnormal bleeding, a prolonged cough, unexplained weight loss, and a change in bowel movements, among others. There are over 100 different known cancers that affect humans.  The great majority of cancers, some 90–95% of cases, are due to environmental factors. The remaining 5–10% are due to inherited genetics.   Tobacco use is the cause of about 22% of cancer deaths Another 10% is due to obesity, a poor diet, lack of physical activity, and drinking alcohol.  Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants.

Plasma Membrane

The outer boundary of a cell that regulates the movement of substances in and out, maintaining homeostasis and protecting cellular integrity.

Amphipathic phospholipids (have hydrophobic & hydrophilic regions)

prevent free diffusions of ions and molecules, much like your skin prevents free diffusion of your guts.

cholesterol

interspersed in membrane and provide strength

Proteins (also amphipathic)

channels allow control of what enters and leaves the cell. act as receptor sites for hormones, neurotransmitters, etc. used for recognition (Rh protein) so your immune system recognizes the body’s components and doesn’t attack.

Carbohydrate Chains

found on both proteins and lipids. also used for cell recognition (IE ABO blood sugars)

Endoplasmic Reticulum

double lipid layer w/ surface enzymes. may have ribosomes (rough) or not (smooth).

channels for protein secretion. divides cell into components. provide surface for enzymes.

SER involved in lipid synthesis (ie steroids)

testes - lipid (testosterone synthesis)

intetsine - triglycerol sythesis

liver - detoxification

Ribosomes

aggregates of protein and RNA

one large and one small subunit. hydrophilic core. made of rRNA. site of translation (making proteins)

Golgi Apparatus

• Folds proteins or adds suagrs for cell recognition. Also secretion.

• Forms lysosomes (sacs filled with digestive enzymes)

Nucleus

mass of DNA associated with RNA and nuclear proteins. have octagonal-shaped nuclear pores

Mitochondia

• Composed of two membranes; both are phospholipid

bilayers like the membrane around the cell.

• The outer membrane is a selectively permeable membrane that surrounds the mitochondria.

• The inner membrane is folded into inward folds called cristae.  Most ATP production in the cell takes place across the cristae. The more cristae present in a mitochondrion, the larger the surface area of its inner membrane – which increases its capacity for energy production. Typically, the more metabolically active a cell, the more mitochondria it will have, and with more cristae per mitochondrion.

• The fluid around the cristae is known as the mitochondrial matrix.  The Kreb’s cycle takes place in the matrix.

• Mitochondria are responsible for creating more than 90% of the energy

needed by the body to sustain life and support growth.                  

• Contain their own DNA (but are incapable of replication w/o

 nuclear help). 

• reduce in number with age and specific diseases

         

Lysosomes

membranes containing digetsive enzymes (proteinases, nucleases, etc)

prominent in macrophages

functions:

autolysis - destroys whole cell

autophagy - destroy old cell

phagocytes - destroy foreign material brought in

lysosomes enzymes are used in meat tenderizers

Microfilaments and Microtubules

compose cytoskeleton

                 b.  form conducting channels for substances in the cytoplasm

                 c.  microfilaments contain actin

                        1.  nonmuscle cell movement (white blood cells can move by themselves

 to migrate to sites of tissue injury to attack bacteria)

                        2.  moving things inside cells (IE. pushing a virus after phagocytosis into

 the cell’s lysosome for digestion)

                 d.  microtubules contain tubulin

                        1.  conducting channels in nerve cells

                        2.  form structure of flagella (sperm tails) and cilia (respiratory hairs)

                        3.  allow movement of centrioles during replication

Centrosomes and Centrioles

centrosome contains two centrioles which are made of microtubules

                 b.  serve as centers about which mictrotubules involved in chromosome                                    movement (during replication) are organized

                 c.  cells without a centrosome (mature nerve cell) cannot reproduce [and                                   therefore cannot be replaced]

                 d.  involved in the production of cilia and flagella

 

Vesicles

a. membranous sacs

b.  much smaller than those found in plants

Cilia

 hair-like extensions of the cell membrane used for filtration.  They

are found lining the trachea and brochi

 

Passive Movement

depend on kinetic energy of individual molecules

Diffusion

scattering of molecules or ions from regions of high concertration to regions of low concentration.

responsible for exchanges of oxygen and carbon dioxide

factors affecting: distance, concentration, molecular weight, temperature.

Facilitated Diffusion

involves use of carrier molecules. only move substances from regions of higher concentrations to lower concentrations.

responsible for movement of glucose across phospholipid bilayer

Osmosis

movement of water across a selectively permeable membrane from an area                         of higher water conc. to an area of lower water conc.

           

                c.  RBC lose water in a hypertonic solution (crenation), gain water in                                        hypotonic (hemolysis), and are normal in an isotonic solution

Filtration

movement of water and dissolved substances across a selectively permeable membrane by pressure

Dialysis

seperation of large and small molecules by diffusion across a selectively permeable membrane.

used clinically

Active Transport

movement of ions and molecules from regions of low conc. to regions of high conc.  It requires energy to be expended (ATP) and involves the action of carrier molecules in the cell membrane

phagocytosis

1. process by which the cell membrane engulfs solid particles

2.  membrane surrounds, encloses, and brings into cell

3.  important in cellular immunity

Pinocytosis

1.  process by which cell membrane engulfs tiny droplets

2.  the liquid becomes surrounded by a vacuole

Receptor-Mediated Endocytosis

receptor molecules on cell surface combine with specific molecules,                                               combinations are ingested

Exocytosis

Export of substances by reverse endocytosis

Gap Junction

1.  allow small, water-soluble substances to pass directly from the cytoplasm of                             one cell to the cytoplasm of another

2.  connect cells electrically and metabolically

3.  plants have special junctions called plasmodesma (ta)

Flagella

Tails.  The only example in humans are sperm tails