BIOL 1216- Intro and Physiology Background

Lecture 1

Homeostasis

• maintaining a stable internal environment

• the body has lots of controlled variables it must keep stable

• ex. body wants to maintain body temp which is at 37 degrees so it will sweat or shiver to maintain it

Integration

• When several components work together to accomplish a function

Homeostasis via Feedback

• feedback systems are the most common way to maintain homeostasis in a controlled variable

Receptor

• senses the change

Control Center

• evaluates whether its outside of the set point

• output when needed

Effector

• produces response to change the controlled variable

Feedback Loop

• a cycle of events where a parameter of the internal environment is monitored, evaluated and changed

Feedback Loop Steps

1. Stimulus

2. Controlled variable

3. Receptors

4. Control center

5. Effectors

6. Response

7. Return to homeostasis

   Repeat

Negative Feedback

• reverse a change in a controlled variable

• how must variables in the body are controlled

Positive Feedback

• strengthens or reinforces a change in a controlled variable

• something external must dispute the cycle

• ex. child birth

Feedforward

• events occur in anticipation of a change in a controlled variable

• ex. mouth watering before eating

When exercising muscles release hydrogen ions into blood what happens to the pH

• blood pH decreases

Lowest set point for pH (where is it most acidic)

• gastric juice found in the stomach

Describe ATP

• releases energy when a phosphate bond splits

• consists of an adenine molecule, ribose molecule and 3 phosphate groups

• its the energy currency of the cell

What can the body breakdown to produce ATP

• carbohydrates

• protein

• fat

Enzymes are examples of catalysts and they function by:

• lowering the amount of energy needed (making it easier) to start a reaction

Correct steps of cellular respiration

1. glycolysis

2. krebs cycle

3. electron transport chain

3 main parts of a human cell

• a flexible plasma membrane separating the cells internal environment from the external environment

• the cytoplasm including cytosol and organelles

• the nucleus that houses most of the cells DNA

ATP

• energy currency

• break apart bond on the 3rd phosphate group to release energy

• energy captured to do work in the body

• aerobic and anaerobic ATP production

Macronutrients

• nutrients our body uses to pro

Aerobic

• requires oxygen

Anaerobic

• does not require oxygen

Roles of protein

• building materials

• hormones

• enzymes

• acid base balance

• transporters

• antibodies

• provide glucose and energy

Ligand

any molecule or ion that bonds to a site on a protein through weak, non covalent interactions

Binding Site

• the region of protein where the ligand binds

3 main components of the cell

1. plasma membrane: forms cells outer surface

2. cytoplasm: consists of the cellular contents between the plasma membrane and nucleus

3. nucleus: large organelle that houses majority of the cells DNA

Blood glucose is regulated within a set point of about 5mm/L. If the levels go up or down the body acts to return the set point which is an example of?

• negative feedback loop

When blood glucose increases the pancreas releases more insulin. The insulin travels to the liver and tells the liber to take more glucose up from the blood. What is the liver?

• the liver is the effector because it removes glucose from the blood to lower blood glucose levels falling the signal of insulin

• effector creates the change and does the work

Proteins CAN DO. RE DO THIS OENNENENNE

When do we need to get things from outside of a cell to inside of a cell vice vers?

• nutrients, water, oxygen, CO2, sugar into blood stream