Exam 1: Human Physiology- Uark Walker

Describe how the different primary tissues compose organs systems

Define homeostasis

State of dynamic constancy in the internal environment (different for each variable of the body)

Explain negative feedback. (Illustrate this concept by drawing and labeling a negative feedback loop)

A negative feedback loop is a reaction that causes a decrease in function. It occurs in response to some kind of stimulus. Often, it causes the output of a system to be lessened; so, the feedback tends to stabilize the system.

a.Sensors in the body to detect change and send information

b.Integrating center, which assesses change around a set point.

c.Effector, which can make the appropriate adjustments to counter the change from the set-point

examples of negative feedback

thermoregulation and blood sugar regulation

Describe positive feedback and explain how this process functions in the body

occurs to increase the change or output: the result of a reaction is amplified to make it occur more quickly

1.Stimulus causes deviation from set point

2.Cellular response amplifies deviation

3.Further deviation leads to additional cellular response

4.And so on and so on until stimulus stops

*end product stimulates process

examples of positive feedback

childbirth

positive v negative feedback

Positive feedback occurs to increase the change or output: the result of a reaction is amplified to make it occur more quickly. Negative feedback occurs to reduce the change or output: the result of a reaction is reduced to bring the system back to a stable state.

List the four primary tissues and describe the distinguishing features of each type

•Muscle cells

•Neurons

•Epithelial cells

•Connective tissue cells

Muscle Cells and Tissue

•Generate mechanical force

•Three types:

• Skeletal- voluntary

•Cardiac-involuntary

•Smooth-involuntary

Neuron and Nervous Tissue

•Neuron: conduct electrical signals (impulses) to other cells

•Make up the:

•Brain

•Spinal cord

•Nerves

Epithelial Cells and Tissue

•Linings and coverings of organs and cavities

•Specialized for:

-Secretion and absorption (single layer-simple epithelium)

-Protection (multiple layer-stratified epithelium)

•Shape and type of epithelial cell vary per location in the body

•Structure and function may differ on one side of the cell compared to the other (apical vs. basal)

Connective Cells and Tissue

•Connect, anchor and support structures in the body

•Bone

•Cartilage

•Connective tissue proper

-Protein/collagen fibers

-Adipose tissue

•Blood

•Structure: extracellular or connective tissue 'matrix' lies between all the types of connective cells

Identify the body fluid compartments

•Watery solution of dissolved oxygen, nutrients, waste

•Two compartments for the fluid:

•Intracellular fluids (cytosol) 65% of all fluid

•Extracellular fluids

•Plasma

•Interstitial fluid

1/11: integumentary system

skin, hair, nails, primary function is protection

2/11: Muscular System

muscles, tendons, primary function is movement

3/11: skeletal system

bones, cartilage, primary function is structure/support

4/11: nervous system

nerves, brain, spinal cord, primary function is sensory information and response

5/11: circulatory system

(aka cardiovascular system) This system works as the transportation highway for the body. It consists of the heart, blood, and blood vessels. It transports substances such as oxygen, carbon dioxide, and nutrients in the body.

6/11: lymphatic system

Composed of a network of vessels, ducts, nodes, and organs. Provides defense against infection.

7/11: respiratory system

nose, nasal passages, nasopharynx, larynx, trachea, bronchi, and lungs, primary function is the process of gas exchange between the body and the environment

8/11: endocrine system

thyroid, pituitary gland, primary function is to secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells.

9/11: urinary system

kidneys, urethra, bladder, primary function is to cleanse the blood, rids the body of wastes, maintains salt and water balance.

10/11: reproductive system

Reproduce offspring- produce male sex cells (sperm) and female sex cells (oocytes)

11/11: digestive system

body system the breaks down food and absorbs nutrients

Use examples to explain how enzymes function as catalysts

•Enzyme can be defined as a protein catalyst.

•Enzymes increase the rate of a reaction in other words Lowers the activation energy of the reaction

•The reaction could have occurred without the enzyme, just much slower

• Enzyme itself is unchanged

•A single catalyst molecule can act over and over again to catalyze many reactions

•Enzymes end in -ase

Describe how reactant concentrations, activation energy, temperature, and the presence of a catalyst affect the rate of a chemical reaction

1. higher concentrations = faster reaction rate

2. higher activation energy = slower reaction rate

3. higher temperature = faster reaction rate

4. presence of catalyst = faster reaction rate

binding sites

•In order to bind properly proteins must have the right conformational shape.

•The active (binding) site determines the type of chemical that is bound.

•Some sites only bind one ligand while others can bind many ligands.

•the shape of the proteins so important, Example: Drugs. The more sites a drug binds to, the higher the chance of unwanted side-effects.

Ligand

•A ligand is any molecule or ion that is bound to a protein by one of the following forces:

- Electrical attractions

-Weaker attractions due to hydrophobic forces between nonpolar regions on the two molecules

•The region of a protein to which a ligand binds is known as an active site.

•When a ligand binds to a protein the proteins' specific function may either be activated or inhibited

describe the forces that bind ligands and binding sites

Chemical Specificity

-A single protein may have multiple active sites for multiple ligands OR multiple sites for one ligand

-Protein Y is very specific to Ligand C

(increasing the specific molecule shape and active site, increase the specificity 'highest')

Affinity

•The strength of ligand-protein binding is a property of the binding site known as _affinity_.

Saturation

•The term saturation refers to the fraction of total active sites that are occupied at any given time.

•The percent saturation depends on:

• The concentration ligand

• Affinity

Agonist

•triggers response, to activate or increase an action. Often mimics a natural produced ligand.

•Ex. Decongestant-mimic epinephrine but on a subtype receptor of epi

Antagonist

•Molecule that does not activate as the natural ligand would. Often occupies the site blocking the natural ligand and its effect.

•Ex. Antihistamine-a histamine blocker by occupying those binding sites

Define diffusion and list the factors that influence the rate of diffusion

Random movement of molecules from regions of _higher_ concentration to regions of _lower_ concentrations

Affected by:

• Concentration difference (gradient)

• Membrane permeability to each molecule

•Neural membrane at rest is more permeable to K+ than Na+

•Temperature

•Surface area

osmosis

•A difference in concentration of solutes exists on either side of the membrane

•Membrane must be _impermeable_ to the solute making the water move

•The net movement of water is from the side with more water (diluted, low solute) to the side with less water (concentrated, high solute).

osmolality

the concentration of a solution expressed as the total number of solute particles per kilogram.

facilitated diffusion

•No energy is required, channel is specific and movements are diffusional

•High - low

•Ex: Glucose: Polar molecule that needs a transporter

•Transporters may be inserted in the membrane as needed

simple diffusion

•Lipid soluble molecules

•Ions through channel proteins

•Water

active transport

•Involves the use of energy (ATP)to "pump" a molecule against its gradient

•Molecule specific and limited by saturation and the rate of conformational change.

•There are two types of active transport based on the source of energy:

1. Primary - Uses ATP, pump is an enzyme

2. Secondary - Uses electrochemical gradient across membrane

Define the terms isotonic, hypotonic, and hypertonic, and explain why hospitals use 5% dextrose and normal saline as intravenous infusions

-Hypertonic means that the environment outside of the cell has a higher concentration of solutes than the cell itself

-Hypotonic means that the environment outside the cell has a lower concentration of solutes than the cell itself

-5% dextrose and normal saline have the same tonicity as the rest of the body fluids so they do no harm to the cells and allow them to remain isotonic

Explain how the body detects changes in the osmolality of plasma and describe the regulatory mechanisms by which a proper range of plasma osmolality is maintained

Distinguish between passive transport and active transport

primary active transport

Why the pump?

1.Na+ gradient (Na+ is used in secondary transport)

2.Prevents constant osmosis

3.Maintain membrane potential - Counter K + leaks

secondary active transport

•The movement of a molecule (Na+) with its electrochemical gradient is coupled with the movement of a second molecule (ex. glucose)

• Requires that proteins have two binding sites (one for each molecule)

•Transported molecules can be moved in the same or opposite directions (cotransport, countertransport)

•Primary AT will move Na+ back out of the cell maintaining the gradient

Explain the actions of the Na+/K+ pump in detail

Describe the equilibrium membrane potentials for Na+ and K+

Describe the membrane potential and explain how it is produced

•An unequal distribution of charges exists across the membrane, leaving the inside cell negatively charged compared to the outside

Define the role of the Na+/K+ pumps in establishing the resting membrane potential

The sodium-potassium pump moves three sodium ions out of the cell for every two potassium ions it moves into the cell continuously. It, therefore, maintains the large potassium ion gradient across the membrane, which in turn provided the basis for resting membrane potential

Explain secondary messengers using an example

•Regulatory molecules may bind to receptors on the cell membrane but then require a second action to carry out the function of the binding