Unit 1: Intro Flashcards
Physiology
The study of how the body and its parts function; the study of organ systems that maintain homeostasis
Integumentary System
(Skin) Forms the external body covering; protects deeper tissue from injury
- Includes pain receptors, sweat and oil glands
Homeostasis
the body’s mechanism to adapt and maintain a stable internal environment
5 Steps of Homeostasis
- Stimulus produces a change in the variable
- Receptor detects change
- Input information is sent along AFFERENT pathway to control centre
- Output information is sent along an EFFERENT pathway to the effector
- Response of the effector feeds back to reduce effect of stimulus to homeostatic level
Control Centre (Homeostasis)
Responsible for determining the set point, analyzing information and determining appropriate response
Negative Feedback Result
Original stimulus is shut off or reduced in intensity (ex., a thermostat, activates mechanisms when its too hot to cool off or when its too cold to heat up)
Positive Feedback Result
increases the original stimulus to push the variable farther (ex., blood clotting, hormones that soften the cervix during childbirth)
Characteristics of Inorganic compounds
Lack carbon, simpler compounds, includes water, salts, some acids and bases
Characteristics of Organic Compounds
Contain carbon, most are covalently bonded, includes carbohydrates, lipids, proteins, nucleic acids, and ATP
Acids release ___
hydrogen ions (H+)
Bases release ____
Hydroxyl (OH-)
Carbohydrates (composition)
Carbon, hydrogen and oxygen atoms
Carbohydrate classifications (3)
- Monosaccharides (simple sugars)
- Disaccharides (double sugar)
- Polysaccharides (complex sugars/starch)
Lipids (composition)
contain carbon, hydrogen and oxygen; insoluble to water
Lipids (Functions; 3)
- Energy storage: triglycerides (3 fatty acids and one glycerol molecule)
- Cell membranes: phospholipids/lipid bilayer (2 fatty acids and a phosphorus containing group for polarity)
- Cholesterol (and steroid) production: cell membranes produce cholesterol (precursor to steroid hormone)
What percentage of body cholesterol is synthesized within body tissue (not from diet)
85%
Proteins (composition and function)
Over half of body’s organic matter; provide construction materials and play a role in cell function; contain carbon, oxygen, hydrogen, nitrogen, and sometimes sulphur
- Made of AMINO ACIDS
Four Levels of Protein Structure
- Primary Structure: the unique sequence of amino acids in the polypeptide chain
- Secondary structure: alpha-helix OR beta-pleated sheet; (reinforced by hydrogen bonds)
- Tertiary structure: the overall 3D shape of the polypeptide (reinforced by chemical bonds between R-groups of amino acids in different regions of the chain)
- Quaternary Structure: some proteins consist of two or more polypeptide chains (ex., hemoglobin contains 4)
Peptides
Chains of amino acids that are much shorter than proteins; used often in medications
Enzymes
Proteins that function as biological catalysts; maintain homeostasis
- Usually end in -ase
Adenosine Triphosphate (ATP)
Composed of a nucleotide built from ribose sugar, an adenine base and three phosphate groups
- The chemical energy used in cells
ADP
result pf energy released from ATP when the high energy phosphate bond is broken (hydrolysis reaction)
Uses for ATP (3)
-Chemical Work: drives energy absorbing chemical reactions
-Transport work: drives the transport of certain solutes across cell membrane
- Mechanical work: activates contractile proteins to perform mechanical work
DNA (Deoxyribonucleic acid)
Genetic material found in the nucleus of the cell; provides instructions for proteins in the body and is organized by complementary bases to form a double-stranded helix
RNA (Ribonucleic acid)
carries out DNA’s instructions for protein synthesis; single-stranded helix
3 types of RNA
- Messenger (mRNA): single strand copy of a gene; nucleus > cytoplasm > ribosomes of endoplasmic reticulum > interacts with rRNA and tRNA
- Ribosomal (rRNA): overseer the assembly of the encoded protein
- Transfer (tRNA): delivers the amino acids used to assemble the protein
Passive Transport
no energy required; osmosis, simple diffusion, facilitated diffusion, and filtration
Diffusion
Particles distribute themselves evenly within a solution (high concentration > low concentration)
Simple Diffusion
unassisted process where lipid-soluble solutes pass through membrane pores
Osmosis
Movement of water cross the membrane; highly polar water molecules pass through aquaporins
Active Transport
Requires ATP; against a concentration gradient
Solute Pumps
involved in the transport of amino acids, some sugars, and ions; ATP energizes the protein carrier and in most cases substances move from low to high concentration
- EX: sodium-potassium pumps
Sodium-Potassium Pumps (3 steps)
- Na+ binds and stimulates phosphorylation of the pump by ATP; changes shape of the pump, opens to extracellular side
- Na+ is expelled and K+ binds to the pump, phosphate group is released, pump returns to original shape
- K+ is expelled to the intracellular side and Na+ sites are open so the cycle can continue
Bulk/Vesicular Transport (2)
- Endocytosis: moving substances INTO a cell (consumption)
- Exocytosis: moving substances OUT of a cell (secretion)
