CytologyChapters 3 & 4 - Anatomy

What are Cells? Cytology: study of cells Structural unit, building block

Estimated ~ 37.2 trillion cells Dependent on health, medical conditions, etc.

Healthy liver has 240 billion cells in it, but some studies on cirrhosis have found the diseased liver has few as 172 billion

Carry out functions critical to life Take in food and oxygen: ingestion, respiration,

digestion Produce heat and energy: metabolism Move and adapt to their environment: motility, transport Eliminate wastes: excretion Perform special functions: secretion Reproduce to create new identical cells

Breakdown of a cell… Cytoplasm

Fluid inside the membrane; contains water, food, organelles, and other special materials

Organelles Nucleus: “brain” of cell; controls many cell activities, including

production Nucleolus: within nucleus; important in reproduction (RNA) Chromatin network: located in nucleus; forms chromosomes Centrosome: located in cytoplasm near nucleus; contains 2 centrioles Mitochondria: “powerhouse” of cell; helps produce energy Ribosomes: protein synthesis Endoplasmic reticulum: transport system of channels

Smooth ER: lipids, Rough ER: proteins Lysosomes: sacks of digestive enzymes; garbage can of the cell Golgi apparatus: synthesizes carbs; packaging of materials Vesicle: fluid filled sack Vacuole: containers

CELL MEMBRANEOuter protective covering of cell

Semipermeable: allows certain substances to enter and leave cell while preventing the passage of other substances Phagocytosis: “cell eating”, engulfs solids i.e.

proteins, dead bacteria, dead cell debris Pinocytosis: “cell drinking”, engulfs liquids i.e. nutrient

absorption in small intestine

Exocytosis: removes particles from the cell i.e. hormones, neurotransmitters, mucus, waste

Cell Transport and Tonicity

Passive Diffusion Simple Diffusion – lipids, through the membrane Facilitated Diffusion – protein channels

Active Transport Protein pump, requires ATP

Tonicity Hypotonic

Hypo- = below/under Solute < water

Isotonic Iso- = equal Solute = water

Hypertonic Hyper- = over Solute > water

Simple vs. Facilitated diffusion

inside cell

outside cell

lipidinside cell

outside cell

H2O

simple diffusion

facilitated diffusion

H2O

protein channel

ACTIVE TRANSPORT Cells may need molecules to

move against concentration gradient need to pump “uphill”

from LOW to HIGH using energy protein pump requires energy

ATP ATP

Who is Henrietta Lacks?

It all started in February of 1951

Dr. George Gey of Johns Hopkins was given a sample of cervical cancer cells that had been taken from young Henrietta Lacks, who was dying of cervical cancer. Why did he want

these cells? What problems

arose when tryingto replicate cells?

Henrietta’s Cells Were Different

Her tumor grew so aggressively that at her autopsy, it was found that her cancer had infiltrated her entire body. 8 months February – October

Uses of HeLa Henrietta Lacks was found to have cervical cancer

in January of 1951 – died October 4, 1951. HeLa cells were used to develop the first polio

vaccine in 1954 by Jonas Salk. At the time millions were suffering from polio.

They were sent into space for experimentation regarding zero gravity in 1960.

HeLa cells helped to produce numerous drugs for diseases including leukemia, influenza, and Parkinson's.

They were also used to develop the cancer drugs and chemotherapy.

Her cells were also later used for advancements like in vitro fertilization, gene mapping, and cloning.

Why Stem Cells? Stem cells allow us to

study how organisms grow and develop over time.

Stem cells can replace diseased or damaged cells that can not heal or renew themselves.

We can test different substances (drugs and chemicals) on stem cells.

We can get a better understanding of our “genetic machinery.”

Stem Cells

What are stem cells? Cells that have the remarkable potential to

develop into many different cell types in the body during early life and growth.

In many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive.

When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

Stem Cell Vocab Two broad types of stem cells: 

Embryonic: isolated from the innercell mass of blastocysts (day 4)

Adult/Somatic: found in various tissues throughout the body  

Two types based on functionality Pluripotent cells can give rise to all of the cell

types that make up the body embryonic stem cells are considered pluripotent.

Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells adult stem cells and cord blood stem cells are

considered multipotent.

Stem Cell Therapy Stem cell therapy is the use of stem cells to treat or prevent a

disease or condition. Bone marrow transplant is the most widely used stem cell therapy Autologous transplantation (AUTO). A patient receives his or her own

stem cells. During the AUTO transplant process, the patient’s stem cells are collected and then stored in a special freezer that can preserve them for decades. Usually the patient is treated the following week with powerful doses of chemo and/or radiation after which the frozen stem cells are thawed and infused into the patient's vein. The stem cells typically remain in the bloodstream for about 24 hours until they find their way to the marrow space, where they grow and multiply, beginning the healing process.

Allogeneic transplantation (ALLO). A patient undergoing an ALLO transplant receives stem cells donated by another person. As a result, the first step for an ALLO transplant is to find a donor match. Specific proteins, called human leukocyte antigens (HLA), are found on the

surface of white blood cells and throughout the body. The combination of these proteins makes each person's tissue unique.

HLA typing is a special blood test that identifies these proteins. A successful bone marrow transplant requires the donation of near-perfect HLA-matched bone marrow. 

REJECTION? Is rejection a possibility? Embryonic vs. Somatic/Adult

Adult stem cells hold a distinct advantage in that a patient's own cells are identified, isolated, grown and transplanted back into the patient. The recipient's immune system does not reject the cells because they are compatible with that person's body.

With embryonic stem cells, the potential for immune rejection would require strong immune suppressing drugs. Risk of microscopic diseases that may be present in the transplanted cells,

as well as other diseases that could be present in the hospital environment. Research

Studies have injected them into the legs of mice with compromised immune systems, the cells thrived and multiplied.

In mice with functioning immune systems, however, the cells began to die within a week and were completely gone after 10 days.

When the researchers tried to inject more stem cells into the mice, their immune systems remembered the foreign invaders, and the cells fared worse—dying in two to four days.