Model 1: Intro Cell Signaling

What is Physiology?

Study of normal function in living systems

What is Pathophysiology?

Study of how and why normal function goes wrong as in human diseases

What are the hierarchical structure of the body?

Cells → Tissues → Organs → Organ Systems → Organism

What is a cell?

The simplest structure units which complex multicellular organism can be divided and still retain the characteristics of life

What are common functions of almost all cells?

1. Cells exchange materials with their environment

2. They obtain energy from organic nutrients

3. They synthesize complex molecules

4. They can duplicate themselves

5. They detect and respond to signals in their immediate environment

What are the four general types of tissue?

Muscle Cells (Myocytes), Neural Cells (Neurons), Epithelial Cells, Connective Tissue Cells

What is a tissue?

An aggregate of differentiated cells with similar properties or functions

What are the three types of muscle tissue?

Cardiac, Skeletal, and Smooth

Which muscle tissue is voluntary?

Skeletal Muscle

Which muscle tissue is involuntary?

Cardiac and Smooth

What is the function of muscle tissues?

Generate mechanical force by contraction

What are the functions of neural tissue?

To initiate, integrate, and conduct electrical signals to other cells

What are the functions of epithelial tissue?

Specialize in selective secretion, absorption of ions and organic molecules, and protection

What are the functions of connective tissue?

To connect, anchor, and support structures of the body

What is an organ?

A collection of tissues joined in a structural unit to serve a common function

What is an organ system?

Organs that are linked together to serve and overall function

How are organisms and organ systems related?

The organism coordinate the activities of these organs systems to maintain a stable internal environment

What is the “internal sea” of cells?

Extracellular Fluid

The extracellular fluid is split into two comparments called….

Interstitial Fluid and Plasma

80% of extracellular fluid is made up of…

Interstitial Fluid

20% of extracellular fluid is made up of…

Plasma

How much of your body is made of water?

60%

What is the volume of body fluid compartment for intracellular fluid?

2/3 TBW

What is the volume of body fluid compartment for extracellular fluid?

1/3 TBW

What seperates the intracellular fluid from the extracellular fluid compartment?

The Cell Membrane

Are intracellular fluid and extracellular fluid similar in composition?

No, they are very different

What seperates the interstitial fluid from the blood plasma?

The Capillary Wall

Are Interstitial Fluid and Plasma similar in composition?

Yes, but one big difference is plasma contains proteins while interstitial fluid contains very few proteins

What is it called when there is too much interstitital fluid?

Edema

What is homeostasis?

The relative constancy of the internal environment

Cells are ____ sensitive to the composition of the fluid that surrounds them

VERY

If there is a change in extracellular fluid composition the body intitates reactions to correct or to minimize that change. What are these mechanisms called?

Homeostatic Control Systems

What is a negative feedback system?

A homeostatic control system that keeps a variable within a certain range

What is a reflex?

A biological control system that directly links a stimulus with a response

What is a stimulus?

A detectable change in the controlled variable

What is a receptor?

The sensor on which the stimulus acts?

What is the structure of a physiological reflex?

Integrating center → Efferent Pathway → Effector → Response → Negative Feedback → Stimulus → Receptor → Afferent Pathway → Integrating Center

What is a feedforward mechanism?

A mechanism that anticpates changes in the environment and minimizes fluctuations

What is a positive feedback mechanism?

Acclerates a process, leading to an “explosive” system

What is a hormone?

A chemical messenger secreted by endocrine cells into the blood stream?

What is a neurotransmitter?

A chemical messenger released by a neuron to affect a muscle gland or nerve

What is paracrine agent?

A chemical messenger released by a cell that acts on nearby cells

What is autocrine agent?

A chemical messenger released into the interstitial fluid that acts upon the very cel that secreted it

If the combined action of regulatory responses result in an overall Loss>Gain of substances it is considered a?

Negative Balance

If the combined action of regulatory responses result in an overall Gain>Loss of substances it is considered a?

Positive Balance

What are polar molecules?

Polar molecules have positively and negatively charged ends, they surround themselves with other polar molecules

What are non-polar molecules?

Non-polar molecules surround with other molecules

Water is a ____ molecule

Polar

Oil is a ____ molecule

Non-Polar

Phospholipids have a polar ____ and an non-polar ____

Head, Tail

The non-polar fatty acid chains are _____

Hydrophobic

The polar heads of phospholipids are _____

Hydrophilic

What are the cell membrane functions?

1. Act as a selective barrier

2. Communication Between Cells

3. Connectin Cells

4. Anchoring Cells

5. Functions are carried out by cell membrane proteins

What is the function of integral proteins?

Transport molecules and cell communication

What is the function of peripheral membrane proteins?

What is the location of integral proteins?

Embedded within the lipid bilayer, amphipathic

What is the location of peripheral membrane proteins?

Attached to the inner or outer membrane surface, only has polar molecules

Substance that dissolve in lipid and diffuse rapidly across cell membranes are….

Non-polar substances

Substances that cannot dissolve in lipid and diffuse rapidly across cell membrane and need a channel are…

Ions

If there is high temperature diffusion will have ____?

More movement

What us responsible for simple diffusion?

Brownian Motion

What is flux?

The amount of material crossing a surface per time?

What is net flux?

The difference between the two fluxes

The net flux is always for a region of _______ to a region of ______

Higher concentration, Lower concentration

Does the body need to supply energy for diffusion?

No!

What facots are influencing net flux?

1. Temperature

2. Molecular Mass

3. Surface Area

4. Viscosity of the Medium

What are three ways ion channel can be gated?

Ligand, Voltage, Mechanically

What is a ligand-gated channels?

Open or close when molecules bind to them

What is a voltage-gated channels?

The membrane potential changes

What is a mechanically-gated channels?

The membrane is stretched

Small non-polar molecules can diffuse down their concentration gradient by….

The lipid membrane

Small ion molecules can diffuse down their concentration gradient by….

Open channels

Can ions go against their electrochemical gradient freely through open channels?

No

What is a carrier?

Type of transporter used by both mediated and vesicular transport

How do mediated transporters work?

1. Expose a binding site to one side of the membrane

2. They change shape and release the solute on the other side of the membrane

What are the rules of protein-ligand binding rules?

1. They exhibit specificity

2. They require a conformational change in shape

3. They are limited in number and displays saturation

What are two types of mediated transport?

1. Facilitated Diffusion

2. Active Transport

Does facilitated diffusion require cellular energy?

No

What are characteristics of facilitated diffusion?

1. Does not require cellular energy

2. Uses a transmembrane protein as a carrier

3. Has Chemical specificity

4. Displays saturation

What are some differences between diffusion and facilitated diffusion?

1. Facilitated diffusion requires a carrier protein

2. Facilitated diffusion has chemical specificity

3. Facilitated Diffusion displays saturation

What are some similarities between diffusion and facilitated diffusion?

1. They do not require cellular energy

2. Molecules are moved down the concentration gradient

What creates the electrochemical gradient?

Active Transport

Where is the energy provided for Active Transport?

The hydrolysis of ATP by the carrier protein

Intracellular fluid have a _____ concentration of K+ and _____ concentration of Na+

High, Low

Extra cellular fluid have a _____ concentration of K+ and _____ concentration of Na+

Low, High