EXSC2530 Quiz 1

Intro, homeostasis, cell physiology I and II

Physiology

Study of the functions of the human body; chemical and physical events

Chemical events

Chemical signals from cells of the nervous system and chemical energy from carbohydrates, lipids, proteins

Physical events

Physical interactions between proteins that cause myofibers to contract or shorten

Homeostasis

Maintenance of relatively constant conditions in the body

Conditions of homeostasis

Volume, temp, chemical content.

Normal range

Values that cells, tissues, organs, and organ systems function normally

The magnitude of oscillations ___.

varies

Small magnitudes of oscillations

pH, body temp, BP

Large magnitude of oscillations

Glucose

____ provides some indication of the relative importance of a variable to homeostasis

Degree of oscillations

__ loss in homeostasis in one or more variables is tolerable

Temporary

___ loss in homeostasis causes problems which are revealed by signs and symptoms

Chronic

Signs are __

Objective evidence

Symptoms are __

Subjective evidence

Set point

The average value over a period of time

Set points are __

Dynamic (change as a result of aging, disease, diet, and exercise)

__% of body mass is composed of fluid

60

__% of body fluid is intracellular

70

__% of body fluid is extracellular

30

___% of extracellular fluid is made up of plasma

20

___% of extracellular fluid is made up of interstitium

80

__ serves as a means through which cells throughout the body can communicate with each other

Extracellular fluid

The cell that produces the chemical

Autocrine

Different cells that reside in the same tissue

Paracrine

Cells in a different organism

Endocrine

Cells communicate with each other by __

Releasing chemicals into the extracellular fluid

Short range cell-to-cell communication

Cells within a tissue are making something that other cells in the same tissue need

Long range cell-to-cell communication

Circulate in blood. Secretion occurs and influences cells in a different organ system

Short range cell-to-cell communication is also known as

Autocrine and paracrine

Long range cell-to-cell communication is also known as

Endocrine

Intracellular fluid

Contributes to the maintenance of cel size and serves as a means through which components of a cell can communicate with each other

Decrease in fluid volume means

Concentration increases

Increase in fluid volume means

Concentration decreases

Enzymes are sensitive to ___

Temperature

Homeostasis is maintained through __

Feedback control mechanisms

Intrinsic feedback control

Processes that are built in into cells, tissues, and organs within a physiological system that allows them to maintain their homeostasis without the help of other physiological systems. Autocrine or paracrine

Extrinsic feedback control

Cells, tissues, and organs in a physiological system that are dependent on cells, tissues, and organs in a different physiological system to maintain their homeostasis. Endocrine

Simple negative feedback

Final response is opposite of initial response

Antagonistic effectors

Effectors that have opposing actions

__ increases HR

Sympathetic

__ decreases HR

Parasympathetic

__ decreases blood glucose

Insulin

__ increases blood glucose

Glucagon

Positive feedback

Effector causes an amplification of the initial response (more of the same)

All feedback loops contain a __

Sensor

Most positive feedback mechanisms are embedded in a ___

Negative feedback loop (e.g. activation of blood clotting factors, child delivery)

Cells are __

The basic units of structure and function in the body

Changes in chemical composition of cells within a tissue or organ will ultimately ___

Influence the function of the organ system and organism

Composition of plasma membrane

Lipids, proteins, cholesterol, glycolipids, glycoproteins

Integral proteins

Span the entire width

Peripheral proteins

Either on intracellular or extracellular surface

Fluid portion of model

Structures are able to move through the plasma membrane, “float” between the phospholipids, like globular proteins.

Mosaic portion of model

Appear in random pattern, like protein

Water soluble

Dissolve in extracellular and intracellular fluid (like glucose, sodium, potassium, insulin)

Lipid soluble

Limited ability to dissolve in extracellular and intracellular fluid (like oxygen, carbon dioxide, and cortisol)

Hydrophobic area of plasma membrane __

Restrict passage of water soluble molecules and allows lipid soluble molecules to diffuse across the membrane

Integral membrane protein functions:

Channels, carrier proteins, receptors, and adhesion molecules

Integral protein channels are __

Bidirectional depending if the channel is open or closed, like a standard door

Integral protein carriers __

Are bidirectional, like a revolving door

Integral protein receptors __

Serve as a means through which the chemical message contained within a water soluble molecule can be delivered to a cell, has a chemical receptor bind to it.

Peripheral proteins extracellular surface

Enzymes, adhesion molecules, and receptors or foreign agents

Peripheral proteins intracellular surface

Enzymes, anchoring site for intracellular proteins

Cholesterol functions

Influences membrane fluidity

Glycolipids functions

Aggregation of cells, cell-cell interactions

Glycoproteins functions

Aggregation of cells, cell-cell interactions, receptors

Plasma membrane functions

Form basic structure of a cell, selective permeable barrier, detects and conveys chemical messages via receptors, link adjacent cells via membrane proteins to form tissues, anchor for intracellular structures

Cytoplasm

Portion of the cell interior not occupied by the nucleus

Fluid portion of cytoplasm

Cytosol or intracellular fluid

Cytosol or intracellular fluid contains __

Cytoskeleton and organelles

Cytoskeleton functions

Structural support, anchor for organelles, movement of organelles/vesicles in cytoplasm, and movement of a cell

Nucleus

Largest organelle, all cells in the body have a single nucleus except skeletal muscle cells/ fibers which are multinucleated, and red blood cells/platelets which have no nucleus

Nucleus function

Storage and transmission of genetic info contained in DNA or genes, and hosts protein synthesis

Rough ER

Bulk of protein synthesis occurs

Smooth ER

No protein synthesis, synthesis of lipids, post transitional modification of proteins, and stores and releases calcium in some cells

Golgi apparatus

“Packaging warehouse” -- receives and sorts packages (vesicles containing proteins)

Lysosomes

Contains digestive enzymes and chemicals capable of degrading components of the cytoplasm, and eliminating/killing micro-organisms

Mitochondria

Has two lipid bilayers, RBC have no mitochondria. Function: Site of ATP production via consumption of oxygen

Simple diffusion

Movement of a molecule from an area of high concentration to low concentration without the investment of energy

Osmosis

Net diffusion of water from an area of high concentration to low concentration

The greater the solute the __ the water

Lower

The lower the solute the __ the water

Greater

Solute and water concentrations are __

Inversely related

Facilitated diffusion

Transport of water soluble molecules from high to low concentration via an integral protein (carrier), is bi-directional

Un-stimulated/basal state

Allows for basal/low level uptake of a specific water soluble molecule

Saturation of facilitated diffusion means __

The maximum rate of diffusion has been reached

Active transport

ATP dependent, transports water-soluble molecules across plasma membranes from low to high concentration

Bulk transport

Hundreds of thousands water soluble molecules are being transported in bulk at the same time. Dependent on energy

Bulk transport (endocytosis)

Internalization of components of the extracellular fluid

Receptor-mediated (endocytosis)

Internalizes the receptor and invaginated membrane until it returns back to the plasma membrane (recycled and reused)

Phagocytosis (endocyotsis)

Performed by types of WBC/leukocytes called phagocytic cells

Bulk transport - Exocytosis

Secretion of intracellular components to the extracellular fluid

What would happen to a cell size if the rate endocytosis > exocytosis?

Cell size would be reduced

What would happen to a cell size if the rate exocytosis > endocytosis?

Cell size would be larger

Membrane potential is __

A voltage difference across a plasma membrane

Intracellular surface has a __

Negative charge (membrane proteins, ATP)

Extracellular surface has a __

Positive charge (Na+)

Electrochemical force

Opposite charges are attracted to each other

Diffusion force

Concentration gradient across membrane

Movement of Na/K only occurs when the channels are __

Open, regardless of an electrochemical or diffusion forceV

Voltage regulate ion channels

Open/close in response to changes in the membrane potential