Chapters 3 & 4 - Anatomy

 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

 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

Outer 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

 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

inside cell outside cell lipid inside cell outside cell H2OH2O simple diffusion facilitated diffusion H2OH2O protein channel

 Cells may need molecules to move against concentration gradient  need to pump “uphill” from LOW to HIGH using energy  protein pump  requires energy 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 trying to 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,  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  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.

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 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.

 Two broad types of stem cells:  Embryonic : isolated from the inner cell 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.

 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.