Human Anatomy/Physiology Unit 1 Part 1

Exam 9/14-9/15

Physiology

The study of body functions

Anatomy

The study of body structure

Atoms

All matter is made up of these tiny molecules

Molecules

A chemical substance formed by the linking of atoms; the smallest unit of a given chemical substance

Cells

The smallest unit capable of carrying out the processes associated with life; the basic unit of both structure and function in living organisms

Plasma Membrane

A protein-studded lipid bilayer that encloses each cell, separating it from the extracellular fluid

Tissues

A functional aggregation of cells of a single specialized type, such as nerve cells forming nervous ____. Also the aggregate of various cellular and extracellular components that make up a particular organ such as lung _____.

Muscle Tissue

A functional grouping of cells specialized for contraction and force generation

Nervous Tissue

A functional grouping of cells specialized for initiation and transmission of electrical signals

Epithelial Tissue

A functional grouping of cells specialized in the exchange of materials between the cells and its environment; lines and covers various body surfaces and cavities and forms secretory glands

Connective Tissue

______ that serves to connect, support, and anchor various body parts; distinguished by relatively few cells dispersed within an abundance of extracellular material

Organ

A distinct structural unit composed of two or more types of primary tissue organized to perform one or more particular functions (ex: stomach)

Body System

A collection of organs that perform related functions and interact to accomplish a common activity that is essential for survival of the whole body (ex: Digestive system)

External Environment

The environment surrounding the environment

Internal Environment

The body’s aqueous extracellular environment, which consists of the plasma and interstitial fluid which must be homeostatically maintained for the cells to make life-sustaining exchanges with it.

Intracellular Fluid (ICF)

The fluid collectively contained within all the body cells

Extracellular Fluid (ECF)

All the fluid outside the cells of the body consists of interstitial fluid and plasma

Plasma

The liquid portion of the blood

Interstitial Fluid

The portion of the extracellular fluid that surrounds and bathes all the body cells

Homeostasis

The ability for the body to maintain an ever-changing internal environment, yet keep change within tightly regulated ranges; many cells, organs, body systems involved in maintenance of homeostasis

Dynamic Steady State

Changes that occur are minimized by compensatory physiological responses. The term ______ *refers to each homeostatically regulated factor being marked by continuous change, whereas _________ ________* implies that these changes do not deviate far from a constant, or steady, level.

Homeostatic Control System

A regulatory system that includes a sensor, integrator, and effectors that work together to bring about a corrective adjustment that opposes and original deviation from a normal set point

Negative Feedback

A regulatory mechanism in which a change in a controlled variable triggers a response that opposes the change, thus maintaining a relatively steady set point for the regulated factor (ex: thermostat)

Common regulatory mechanism in body for maintaining homeostasis

Controlled Variable

Some factor that can vary but is held within a narrow range by a control system

Sensor

The component of a control system that monitors the magnitude of the controlled variable (thermometer, senses that the room decreased in temp)

Set Point

The desired level at which homeostatic control mechanisms maintain a controlled variable (temp thermostat is supposed to be at)

Integrator

A region that determines efferent output based on processing of afferent input; also called a control center (Thermostat)

Effector

The component of a control system that accomplishes the output commanded by the integrator (Furnace, which then leads to increase in room temp)

Positive Feedback

A regulatory mechanism in which the input and the output in a control system continue to enhance each other so that the controlled variable is progressively moved further from a steady rate (ex: birth)

Phospholipid

These have a polar head containing a negatively charged phosphate group and two non polar fatty acid chain tails

Amphipathic

2 Domains

Cholesterol

Essential for the most common way to adjust fluidity

A type of fat molecule that serves as a precursor for steroid hormones and bile salts and is a stabilizing component of the plasma membrane

Hydrophilic

“Water-Loving”; can interact with water molecule

Hydrophobic

“Water-Hating”; does not mix with water

Lipid Bilayer

Basic structure, structural backbone, barrier to water soluble substances, fluidity

Phospholipids assemble themselves into these double layers of lipid molecules. Hydrophobic tails bury themselves into this away from the water and the hydrophilic heads line up on both sides in contact with the water. This is more fluid than rigid with the consistency of oil.

Unsaturated Fatty Acid

One or more double-bond

Has the cis-double bond (increases bilayer fluidity)

Saturated Fatty Acid

Only contain one single bond

Flippase

Transmembrane transporter enzymes responsible for asymmetric phospholipid bilayer

Transmembrane Proteins

EMBEDDED through the entire thickness of the lipid bilayer membrane.

Integral membrane proteins

More than one membrane spanning domains (non-polar amino acids)

Move lipophobic molecules across cell membrane (selectively permeable) through channels and carriers

Peripheral Membrane Proteins

Exposed to only one side of the membrane; anchored to cytosolic side or extracellular fluid side in a variety of ways.

ONLY ON ONE SIDE AND ATTACHED TO TRANSMEMBRANE PROTEIN

Polar molecules that do not penetrate the membrane. A plasma-membrane protein that studs the surface instead of penetrating the membrane.

Fluid Mosaic Model

The view of membrane structure. This is in reference to the membrane fluidity and the ever-changing ______ pattern of the proteins embedded in the lipid bilayer.

LIPID BILAYER WITH INSERTED PROTEINS

Glycocalyx

Outer surface of membrane covered with a dense carbohydrate coat

Leak Channels

Unregulated, undated channels that are open all the time

Gated Channels

May be open or closed to their specific ion as a result of changes in channel shape in response to controlling mechanisms

Membrane Bound Enzymes

Proteins located on either the inner or the outer cell surface function as this which controls specific chemical reactions

Receptors

Recognize and bind specific molecules in the environment of cell

Binding initiates series of membrane and intracellular events that alter activity of the cell

Membrane protein that binds with specific extracellular chemical messenger, bringing about membrane and intracellular events that alter the activity of the particular cell

Cell Adhesions Molecules (CAMs)

Proteins that protrude from the surface of the plasma membrane and form loops or other appendages that the cells use to grip one another and surrounding connective tissue fibers

Interact with cadherins and interns

Cadherins

Interaction with ECM and other cells

Desmosomes

Anchor adjacent cells together-confer stability to cell layers (cell adhesion cells)

Present in skin, cardiac muscle, uterus - where integrity of layers important

Major structural elements of these are plaque, glycoproteins filaments extracellularly, and intermediate filament scaffolding

An adhering junction between two adjacent but non touching cells formed by the extension of filaments between the cells’ plasma membranes; most abundant in tissues that are subject to considerable stretching

Plaques

A deposit of cholesterol and other lipids, perhaps calcified, and thickened, abnormal smooth-muscle cells within blood vessel walls as a result of atherosclerosis

Tight Junctions

Adjacent cells firmly adhere to each other by fusion of junctional proteins on outer surfaces of adjacent plasma membranes

Present in sheets of epithelial tissue (intestinal epithelium, vascular endothelium)

Form highly selective cellular barriers to macromolecule movement - very dynamic

Maintain apical/basal cell membrane asymmetry

Gap Junctions

Protein channels between adjacent cells that allow passage of small water-soluble particles between cells

Formed by complex of cylindrically-arranged connexion subunits

Present in tissues where synchronized activity of cells is very important - cardiac and smooth muscle - functional syncctium

A communicating junction formed between adjacent cells by small connecting tunnels that permit passage of charge-carrying ions between the cells so that electrical activity in one cell is spread to the adjacent cell

Connexons

Made up of 6 protein subunits arranged in a hollow, tubelike structure that extends though the thickness of the plasma membrane

Anatomy vs. Physiology

Relationship of form (structure) and function

ALWAYS A RELATIONSHIP BETWEEN

Small Intestine Anatomy/Physiology Relationship

Foldings (structure) = increased SA

Increased SA = Increased Absorption (Function)

Chemical Level of Organization

A molecule in the membrane that encloses a cell is an example of…

Cellular Level of Organization

A cell in the stomach lining is an example of…

Tissue Level of Organization

Layers of tissue in the stomach wall is an example of…

Organ Level of Organization

The stomach is an example of…

Body System Level of Organization

The digestive system is an example of…

Organism Level of Organization

The whole body is an example of…

Molecules > Cells > Tissues > Organs > Systems > Organism

Levels of organization in the body

Equilibrium

Interstitial Fluid and Plasma are…

Interstitial Fluid

Homeostasis regulates plasma which then regulates…

Homeostasis

Essential for survival of each cell

Deviation in controlled variable > detected by the sensor > Informs the integrator > sends instructions to the effector(s) > Brings about compensatory response > results in controlled variable being restored to normal

What are the components of a negative feedback control system

Fall in Room Temp > Thermometer senses and informs > Thermostat receives information and sends instructions > Furnace brings about what the thermostat informed > resulting in increase heat output

Describe how a thermostat is like a negative feedback example

Negative Feedback

The most common form of homeostatic regulator

Positive Feedback

Gets things done quickly and increases change

Uterus (smooth muscle has oxytocin receptors)

Increase in estrogen

Increase # of oxytocin receptors

Increase uterus sensitivity

Increase contractions

Increase cervix pressure

Increase serotonin oxytocin

Increase contraction

Increase Oxytocin

Leading to BIRTH (Climatic Event)

How is pregnancy similar to a positive feedback example

The 5 general functions of biological membrane

1. Physical Isolation (separation/creates compartments)
2. Regulation of exchange with the environment
3. Resting membrane potential - electrochemical gradient (voltage; block of material)
4. Communication between cell and environment (signaling)
5. Structural Support (connected to cytoskeleton)

Proteins and Lipids and a small amount of Carbs

Biological membranes are predominantly…

30-50%

Typical amount of protein in a biological membrane

40-60%

Typical amount of lipids in a biological membrane

10%

Typical amount of Carbohydrates in a biological membrane

Protein molecules

Embedded in the lipid bilayer and mediate most other functions of membrane

ECF side

Carbs are attached to which side? aka being attached to lipids and proteins (glycolipids)

Trilaminar Structure

The lipid bilayer is a _____________ structure due to the arrangement of membrane lipids

Membrane lipids

1. Amphipathic Lipids (2 domains; head and tail)
2. Phospholipids predominate
3. Glycerol Backbone
4. Polar head - glycerol phosphate head group
5. Non-polar tails - Hydrocarbon chains

Lipid Heads

Negatively charged

Polar

Hydrophilic

Lipophobic

Lipid Tails

Positively Charged

Non-Polar

Hydrophobic

Lipophilic

VaryP

Phospholipids _____ in composition

Phosphate head group

Fatty acid makeup

Phospholipid Bilayer

\

Micelle

Liposome

1. Bilayer
2. Micelle
3. Liposome

Phospholipids spontaneously assemble into what three different possibilities when in contact with water

Factors that influence bilayer structure

1. bilayer is very dynamic
2. fluidity depends on temperature
3. fluidity depends on composition (hydrocarbon chain size/cis double bonds; cholesterol)

Dynamic Two Dimensional Fluid

A lipid bilayer is a….

* Lateral diffusion is very rapid (average lipid molecule diffuses length of an average bacterial cell in about one second)
* Flip-Flop rarely occurs and only does if flippase enzyme catalyzes (once a month for individual molecule)

Bad rep for cholesterol?

This gets a bad rep because the body struggles to dispose of it because its only way to do so is for liver to turn it into bile and put it into the digestive tract

1. polar domain - OH group
2. Planar steroid rings - rigid
3. Nonpolar tail

What 3 main things does cholesterol have?

Cholesterol in Membranes

1. Inserts into bilayer between phospholipid molecules
2. Orients in bilayer with -OH groups close to polar heads. of phospholipids
3. Plate-like steroid rings interact with and immobilize first - CH2 groups of phospholipid hydrocarbons (decreases fluidity of bilayer)
4. Decreases bilayer permeability to water and small water soluble molecules (Blocks openings between phospholipid tails)

Reduces Molecular Movement -- RIGID

Inserting itself into bilayer between phospholipid molecules

Decreases fluidity of bilayer

Plate-like steroid rings interact with and immobilize first -CH2 groups of phospholipid hydrocarbons

Blocks openings between phospholipid tails

Decreases bilayer permeability to water and small water soluble molecules

1. Vary Composition of Phospholipid
2. Vary Cholesterol

How can you change bilayer

Diverse and Asymmetrical

Lipid Bilayer composition is…

Membrane function

Why is there a different # of lipids in membranes

1. Amphipathic
2. Single Pass
3. Multipass

What are the three transmembrane protein spanning domains?

Cytoplasmic and Extracellular Domains

What 2 domains are polar in transmembrane proteins

Alpha-helix

Membrane spanning domain forms….

(peptide bonds form H-bonds with one another, at least 20 a.a for 1 pass)

* Single pass and multipass membrane proteins