Exam 1 - Lecture 1 8/23 Flashcards
How many cells are in the human body?
35 trillion cells
Another name for internal environment
Extracellular fluid
Types of waste products
CO2, H+, Solid waste, H2O, urea
How does H2O become waste?
A chemical reaction
Negative feedback
Sees a change in the body, DOES THE OPPOSITE. Change is NEGATIVE to the stimuli.
How do the kidneys maintain homeostasis?
Maintaining BP, fluid buffering, pH
Is the following positive or negative feedback?
Increased CO2 -> Increased Ventilation = decreased CO2 back to normal
Negative feedback
Is positive feedback good or bad?
Can be both.
Positive Feedback
Amplifies change AFTER change is detected. Stimuli causes a change, and the body amplifies it.
Decreased MAP -> Increased AVP/ADH = Increased MAP back to normal
Negative feedback.
Vasopressin (ADH) is secreted from pituitary gland to raise blood pressure.
Vicious Cycle
Can and are usually avoided in physiologic positive feedback loops, by checkpoints.
Checkpoint
Occurs when positive feedback is no longer needed. E.g. once baby is born, oxytocin no longer needs to be secreted to dilate cervix.
Positive feedback from clotting
Clotting cascade stops the bleed, once bleed is stopped then checkpoint kicks in and stops the positive feedback. Vicious cycle occurs when checkpoint does not occur, and body continues to clot unnecessarily and causes severe injury/death.
Examples of Pathologic positive feedback
- Sepsis/necrosis: dead cells release debris and kill cells around them, such as releasing potassium.
- Severe acidosis: so acidotic that CNS can’t increase respiratory drive, resulting in CO2 continuing to climb.
- Nephron cells die, and nephron cells do not regenerate. Remaining nephrons have to pick up more work resulting in more cell death.
- Severe hemorrhage: Decreased map -> decreased coronary blood flow -> decreased cardiac output = even lower MAP -> results in death.
Compensated shock
Negative feedback works well. Less cardiac output from less blood results in increased cardiac output from tachycardia/increased contraction. Can recover from 20% (1L) blood loss.
Decompensated shock
Positive feedback leads to death. 40% blood loss (severe hemorrhage) leads lack of blood to heart = lower map = death.
Do healthy people respond to drugs the same way unhealthy people do?
No.
What changes with the administration of anesthetic drugs
It alters physiology. Natural homeostasis is affected and YOU the provider must take over homeostasis. e.g. body temperature, blood pressure, heart rate, pH
How many RBCs in the human body?
25 trillion
Are cells capable of replication?
Usually. If not, other cells nearby are capable of replicating the other cell. e.g. RBCs can’t self replicate but bone barrow is nearby and creates new RBC’s.
Cells make up ____ which make up _____ organs which make up _____.
Tissues, organs, body.
The cytoplasm is made up of what % of water?
70-75%
What makes up the cell wall?
Phospholipid bilayer.
Where do most of the chemical reactions take place in the cell?
Cytoplasm
Nucleus
Has a barrier to keep DNA secure from viruses and bacteria. Almost its entire own cell wall.
What is the nucleus cell wall composed of>
Double phospholipid bilayer
Nuclear envelope
The area between the outer and inner membranes on nuclear cell wall.
Endoplasmic Reticulum (ER)
Extension of nuclear wall. Genes are read/turned on. Proteins and fats are produced, and stores calcium.
What is formed in the Granular ER (Rough ER)
Proteins
What makes the ER “Rough”?
Ribosomes.
What do ribosomes do in the ER?
Translate amino acids into proteins
What is formed in the Smooth ER?
Lipids
Golgi apparatus
Proteins/lipids are brought here from the ER, where they are then packaged into vesicles and sent into the cytoplasm.
Secretory vesicles
They move the packaged proteins/lipids from Golgi apparatus to dump outside cell. e.g. oxytocin transported to cell wall and outside the cell.
What is the proteins function in the cell membrane?
Transfer compounds across the membrane
DNA is transcribed to produce what?
RNA
After RNA is produced in the nucleus, where does it go?
Outside the Nucleus to be translated by ribosomes into proteins
Where do ribosomes transcribe RNA to proteins?
ER 95% of the time – 5% of ribosomes in the cytoplasm
List the important organelles and their function
- Transport vesicles
- Secretory vesicles: protein packages
- Mitochondria: produce ATP from energy compounds and oxygen
- Lysosomes: digest/destroy things in the cell such as dysfunctional proteins. Very acidic environment to rip everything apart.
- Peroxisomes: digest/destroy, mostly toxins. Heavily found in liver processing ethanol via oxidative stress.
Enzymes
-ase. Usually proteins, Catalyze chemical reactions. e.g. ATPase pumps potassium across cell wall.
Structural components
Internal support to keep shape. e.g. filaments or proteins inside the cell to prop it open.
Sugars, Glyco-, Carboxy-, Carb-
Used for energy, structure, and identification.
-Many inside cell was inside proteins.
-Bacteria can form ID tags as well, so sugar compounds creating ID tags for cells helps the body determine whether the cell is human or bacterial/viral.
- Can also hold cells together, think how sugar is sticky.
- External sugars have a negative charge, and can act to repel other negatively charged compounds. These are common in the kidneys.
Mitochondria DNA
inherited from mother, 12-20 different sets of mitochondrial DNA.
