Exam 1 - Physiology

Lecture 1 - Intro; Lecture 2 - Cell & Membrane Physiology; Lecture 3 - Membrane Transport & Resting Potential; Lecture 4 - The Action Potential; Lecture 5 - Synapses & Transduction

What is Physiology?

The study of function; also known as the study of things that need to be done to stay alive

What is Anatomy?

The study of form

What two studies are forever intertwined?

Anatomy & Physiology

What are the basics of Physiology?

• Experimental, not observational

• There are many subdisciplines, but they all revert to cell physiology

• Complexity rises as cells interact & function with nearby (and distant) cells

What are the levels of complexity?

• Chemical

• Cellular

• Tissue

• Organ

• Body (Organ) System

• Organism

What are the 4 types of tissue?

1. Muscle

2. Nervous

3. Epithelial

4. Connective

What are organs made up of?

Blends of tissues

What does the digestive system do?

1. Processes food for use by the body

2. Removes waste from undigested food

What does the urinary system do?

1. Controls water balance in the body

2. Removes wastes from blood and excretes them

What does the lymphatic system do?

1. Returns fluid to blood

2. Defends against pathogens

What does the respiratory system do?

1. Removes carbon dioxide from the body

2. Delivers oxygen to blood

What does the male reproductive system do?

1. Produces sex hormones & gametes

2. Delivers gametes to female?

What does the female reproductive system do?

1. Produces sex hormones & gametes

2. Supports embryo/fetus until birth

3. Produces milk for infant

What does the muscular system do?

1. Enables movement (with skeletal system)

2. Helps maintain body temperature

What does the nervous system do?

1. Detects & processes sensory information

2. Activates bodily responses

What does the integumentary system do?

1. Encloses internal body structures

2. The site of many sensory receptors

What does the skeletal system do?

1. Supports the body

2. Enables movement (with muscular system)

What does the endocrine system do?

1. Secretes hormones

2. Regulates bodily processes

What does the cardiovascular system do?

1. Delivers oxygen & nutrients to tissues

2. Equalizes temperature in the body

Which systems are the only ones that improve blood?

Digestive, Urinary, and Respiratory Systems

Which system has no care for bodily homeostasis?

Male & Female Reproductive Systems

What is Extracellular Fluid (ECF)?

Fluid outside of cells

What is Intracellular Fluid?

Fluid inside of cells

What are the two components of ICF?

Interstitial Fluid & Plasma

What is interstitial Fluid (ISF or IF)?

Intracellular fluid that bathes the cell directly

What is Plasma?

Intracellular fluid that circulates fuel & wastes to restore the composition of ISF

Homeostasis (think of what is needed to maintain homeostasis)

• Cells can only survive & thrive if ECF is compatible

• Chemical compounds & physical state of environment must be maintained w/in ranges compatible w/ cellular function

• To maintain the ECF requires demands upon the entire organism

How does interaction with the environment simultaneously maintain and endanger conditions of homeostasis?

Internal & external factors can cause a change in homeostasis in an organism. How an organism compensates for that change determines if it will fail or succeed. Failure leads to illness, while success leads to wellness.

What three things must an organism do to maintain homeostasis?

1. Detect a problem & transmit the information (sensor)

2. Comprehend information & combine it with other data to make a plan for adjustment (integrator/control)

3. Make adjustments (via an effector) that restore the original conditions

What is negative feedback?

When change is opposed in the system by driving the variable in the other direction

Is negative feedback stable or unstable?

Stable

What are some examples of negative feedback?

Body temperature regulation, thirst, crossing street as you get to the other side while a car is coming

What is positive feedback?

An increase in stimulus in an organism results in a further increase in stimulus

Is positive feedback stable or unstable?

Unstable

What are some examples of positive feedback?

Drugs, childbirth, o-gasm

What are the components of the cell theory?

• Cell is the smallest structural and functional unit capable of life

• Function of the cell is directly connected to its structural properties (works a certain way because it’s built a certain way)

• Organisms are made of cells, and their structure & function is dependent upon that of their cells

• All cells come from cells

• All cells are similar across life

Central Dogma

Genetics flow in one direction: DNA to RNA to Protein

Transcription

• DNA to RNA

• Performed by RNA Polymerase

Translation

• RNA to Protein

• Performed by the ribosome

What are the two Endoplasmic Reticulum?

• Rough ER

• Smooth ER

What is the job of the Rough ER?

Protein synthesis; tags destination for proteins in the cell

Why is the Rough ER “rough"?

The presence of ribosomes

What is the job of the Smooth ER?

Carbohydrate & Lipid Synthesis

What is translated by Rough ER ribosomes?

Extracellular & Membrane Proteins

What is the role of the Golgi Complex?

Interprets the destination code from the ER; packages proteins into vesicles, that are then trafficked to the correct destination

What are vesicles?

Bubbles of membrane

What is exocytosis?

How a protein leaves the cell when it is destined to do so

What are the two types of exocytosis?

Constitutive & Regulated

Constitutive Exocytosis

• Proteins are continuously packaged to exit the cell

• The vesicles of these proteins fuse with the cell’s membrane and are releases its contents

• Does not need a signal and is used for proteins that must be released constantly

Regulated Exocytosis

• Only excreted when signaled

• The vesicles wait inside the cell until a signal (from a hormone, nerve, etc) tells the vesicle to fuse with the membrane

• Only then is the protein excreted

What are Docking Proteins?

Help vesicles recognize & attach to the correct target membrane before fusion.

What are SNAREs?

Help a vesicle dock & fuse with a target membrane

v-SNARE

• Located on the vesicle

• Binds to t-SNARE on the target membrane

t-SNARE

• Located on the target membrane

• Fuses the vesicle to the target membrane

List the full process of Exocytosis

1. Protein is packed into a vesicle

2. Vesicle travels towards the cell membrane

3. Docking proteins help the vesicle attach to the correct location

4. SNAREs connect & pull the vesicle membrane + cell membrane together

5. Membranes fuse

6. Protein is released from the cell

What is Endocytosis?

How membrane brings substances into the cell

What are the three types of Endocytosis?

1. Phagocytosis

2. Pinocytosis

3. Receptor-Mediated Endocytosis

What is Phagocytosis?

The membrane bringing a particlet into the cell by “eating,” the membrane encapsulates a particle when it is nearby and brings it inside the cell

What is Pinocytosis?

The membrane brings in outside particles by “drinking,” the membrane sips on the extracellular fluid to bring it inside the cell

What is Receptor-Mediated Endocytosis?

Brings particles into the cell by binding through the use receptors; the membrane is coated with receptors that wait for the particles to attach

What coat protein plays an important role in Receptor-Mediated Endocytosis?

Clathrin

What two organelles are in charge of Waste Disposal in the cell?

Lysosomes & Peroxisomes

What is the role of lysosomes?

To use hydrolytic enzymes to detoxify poisons & get rid of debris

What is the role of peroxisomes?

To use oxidative enzymes & water to detoxify poisons & destroy debris

What is Ubiquitin?

The tag for degradation of proteins

What is Proteasome?

The disposal area for protein

What is recycled from proteins

Amino Acids

What is the Mitochondria?

• Create ATP for the cell

What is unique about the Mitochondria?

• Double membrane

• Is a standalone source for DNA (makes proteins not seen anywhere else)

• Has a key role in apoptosis, able to kill the cell quickly

What is the Endosymbiotic Theory?

The mitochondria used to be a bacteria that the human body liked, so it enveloped it & allowed the mito. to make ATP for us

What is Adenosine Triphosphate (ATP)?

The primary energy carrier & currency in living cells

What is energy metabolism?

The process that generates ATP by harnessing it & holding on to energy

Why is energy metabolism associated with “pocket change?”

ATP needs to continuously be produced & used at different times. ATP releases the energy that is needed & stores the rest until it is needed

Summarize what the role of the Plasma Membrane is.

• Thin layer enclosing intracellular contents

• Mechanical barrier

• Gateway for passage in & out

• Maintains differences in composition of ECF & ICF

• Where most physiology happens

What is the Plasma Membrane comprised of?

• Phospholipid bilayer

• Hydrophobic tails

• Hydrophilic heads

• Amphipathic

What is the arrangement of the Plasma Membrane?

• Tails face each other because they are hydrophobic

• Heads face watery environment of ECF & ICF

Is the Plasma Membrane mostly hydrophobic/hydrophilic and polar/non-polar?

Hydrophobic & Non-polar

What is the Fluid Mosaic Model?

A model of the plasma membrane; the membrane itself is fluid but the “tiles” can move, making protein migration possible.

How is membrane function dictated in the Plasma Membrane?

Protein population

What do Carbohydrates do in the Plasma Membrane?

Help with identification & barriers

• Example: carbohydrates in the plasma membrane determine blood type

What are the three ways cells can attach to each other?

1. Desmosomes

2. Tight Junctions

3. Gap Junctions

What are Desmosomes?

Strong mechanical connections between cells that use cadherins on the membrane & filaments in the cytoskeletons of those cells

What are Cadherins?

Used in desmosomes to connect cells mechanically

What are Tight Junctions?

Impede movement between two cells, creating a barrier to migration of proteins along the cell surface; strands of claudin proteins form belts around cells

What are Claudin Proteins?

Impede movement & protein migration between cells by forming belts around the cells

Why must proteins be contained by Tight Junctions?

In order for proteins to work efficiently, they must stay where they are & not float between cells, therefore they are constrained to specific cells

What are Gap Junctions?

“Windows” between cells that are formed by connexon proteins that permit the passage of small molecules/ions

Why are Gap Junctions important?

Some excitable molecules need to coordinate & pass freely through cells to be efficient

What is Membrane Transport?

Control of Difference

What is Permeability?

The membrane controls which substances cross

In terms of permeability, what is the difference between oil and water?

• Oil: hydrophobic, crosses more easily

• Water: hydrophilic, needs more help crossing membrane

What is Passive Membrane Transport?

Downhill movement, does not require an additional energy source

What is Active Membrane Transport?

Uphill movement, requires an energy source

What is Diffusion?

Net movement from HIGH to LOW concentration. This process does not need ATP, but can be slow

What are factors that affect diffusion through the membrane?

• Concentration difference

• Surface area

• Hydrophobicity

• Molecular size

• Membrane thickness

What does diffusion do? (Phrase)

Diffusion dissipates gradients

Explain how water moves through a semipermeable surface with osmosis?

When solute cannot cross the surface but water can, water will cross the surface to the higher salt concentration to establish equilibrium between both sides.

What phrase can explain the relationship between water & salt during osmosis

Where salt goes, water follows

What is Osmotic Pressure?

Tonicity; the ability of an extracellular solution to cause water to go into or out of a cell