Ivy Tech APHY 201 Exam 1

External body surfaces are...

continuous with the external environment

What are the 6 external body surfaces?

1) Nasal and oral passages

2) Respiratory tract

3) GI tract

4) Urinary tract

5) Reproductive tract

6) Ducts of exocrine glands

Internal body surfaces can only be accessed...

from an internal body fluid

or

by transport across an external membrane

What are the 3 internal body surfaces?

1) Cell membranes of cells within the body

2) Cardiovascular and lymphatic membranes

3) Serous and connective tissue membranes

Membranes divide the body into compartments that...

maintain separate chemical environments

What is the external face of the membrane?

the surface facing the environment outside of the body

What is the apical (or huminal) face of the membrane?

the surface facing the lumen of a hallow structure

What is the basolateral face of the membrane?

the surface facing the intestinal environment

What are the 7 fluid compartments of the body?

1) Blood plasma and lymph

2) Interstitial fluid

3) Intracellular fluid

4) Fluid in membranous organelles

5) Cerebrospinal fluid

6) Synovial cavities

7) Chambers in eyeballs and ears

Intracellular fluid contains how much of the body's water?

2/3 (28L)

Extracellular fluid contains how much of the body's water?

1/3 (14L)

(3L blood plasma, 11L interstitial fluid)

Filtration

Pressure driven (blood pressure and fluid hydrostatic pressure)

Diffusion

Driven by concentration gradients

Osmosis

Driven by concentration gradients of solutes (only water)

Routes of water loss

1) Evaporation from skin and moist membranes, sweat (+/- 900mL)

2) Feces (+/- 100mL)

3) Urine (+/- 1.5L)

Routes of water gains

1) Food, beverages (+/- 2.25L)

2) Metabolism (+/- 250mL)

Primary receptors of the thirst mechanism

Hypothalamic receptor neurons signal the thirst center when blood plasma osmolarity > 280 mOsm

Secondary receptors of the thirst mechanism

Osmoreceptors in the mouth detect low volume and increase concentration of saliva

Integrating center

Hypothalamic thirst center

Stimulation of the thirst center causes...

1) Stimulation of water-seeking behaviors through the cerebral cortex

2) Increased water conservation by the kidneys, through ADH from the posterior pituitary

Temporary cessation of thirst

Moistening of oral osmoreceptors (inhibits hypothalamic thirst center only as long as the mouth remains moist)

Long term cessation of thirst

Return to normal plasma osmolarity (strongly inhibits thirst center; as long as plasma osmolarity remains normal, thirst is fully inhibited)

Renal response

Cannot fix dehydration; only reduces water loss

(reduces filtrate formation and increases water absorption from the urine)

Hypothalamic compensations for overhydration

Plasma osmolarity < 280 mOsm strongly inhibits thirst by quieting receptor neurons

Renal Response compensations for overhydration

Increase water loss in urine by increasing filtrate formation and inhibiting water absorption from the urine

Homeostasis

The ability of the body to maintain optimal performance of a system under a given set of conditions

When conditions of homeostasis change...

homeostatic set points change to maintain the optimal performance of the system

Feedback loops

Systems that allow communication between cells to maintain a physiological system within a given range of function

Elements of feedback loops (4)

1) Physical or chemical stimulus

2) Receptors

3) Chemical or electrical signal

4) Target Cells

Physical or Chemical Stimulus

Some component of the internal or external environment that is monitored for changes

Receptors

Structures that monitor the external or internal environment for changes in specific stimuli

Chemical or Electrical Signal

A secreted chemical or electrical potential that allows cells to communicate information abot changes in stimuli with other cells

Target Cells

Cells that receive the signal sent by other cells. Usually involved in producing the appropriate response.

Examples of chemical properties

Size, weight, number of protons or electrons, solubility in water, electrical charge

Atom

The smallest particle of any element

Proton

Subatomic particle with one positive charge and mass of 1 amu (located in the nucleus)

Neutron

Subatomic particle with no charge and mass of 1 amu (located in the nucleus)

Electron

A subatomic particle with a negative electric charge (located in orbitals around the nucleus)

Naturally occurring atoms have...

equal numbers of positive and negative charges

The number of protons in the nucleus determines...

atomic number

What do different numbers of neutrons create?

Isotope

Electrons are involved in...

Form covalent bonds, gained or lost create ions, capture and store energy, create free radicals

The molecular weight of an atom is determined by...

protons + neutrons = atomic mass

Electron compatibility is partly determined by...

how many empty spaces exist around the nuclei of the bonding atoms; this is a chemical property of atoms

Describe the energy levels of electrons based on their position relative to the nucleus

The lowest energy level starts closest to the nucleus and gets stronger farther out

What happens when electrons absorb energy from the environment?

They spin faster, the faster they spin, they can jump into a higher energy level

The energy content of larger molecules is ________ smaller molecules

greater than

Forming chemical bonds ________ energy content of a molecule

increases

Breaking chemical bonds ________ energy

consumers

Covalent bonds

Molecules form when atoms share pairs of electrons, one electron from each atom

Why are covalent bonds typically used to form the structure of a molecule?

These strong bonds require the input of energy to break them apart. There can also be double bonds which are even stronger.

Nonpolar molecule

When a covalent bond is formed between atoms that are of similar size

Polar molecule

When a covalent bond is formed between atoms that are significantly different sizes

How does the charge in the region of the bond near the larger nucleus compare to the region of the bond near the smaller nucleus?

The atoms with the stronger attraction for electrons develops a slight negative charge and the atoms with the weaker attraction for electrons develops a slight positive charge. They can be said to have positive or negative ends, or poles.

Ionic bonds

(AKA electrostatic attractions) result from the attraction between ions with opposite charges

What happens to a molecule when it loses an electron?

The molecule becomes positive

What happens to a molecule when it gains and electron?

The molecule becomes negative

Cations

Positively charged ions

Anions

Negatively charged ions

Hydrogen bonds

A weak attractive force between a hydrogen atom and a nearby oxygen, nitrogen, or fluorine atom. No electrons are gained, lost, or shared.

What is the basic chemical formula for carbohydrates?

CH2O

What are carbohydrates used for by the body?

To store chemical of energy or in the manufacture of chemical energy

Monosaccharide

The building blocks of complex carbohydrates can either have 5 carbons (ribose) or 6 carbons (glucose)

Disaccharide

Consist of glucose plus another monosaccharide (made from 2 simple sugars)

Polysaccharide

Glucose polymers. All living cells store glucose for energy in the form of a polysaccharide

Provide examples for polysaccharides and what kind of organism possesses each example you give:

Chitin (in invertebrate animals), glycogen (in vertebrate animals), cellulose and starch (in plants), dextran (in bacteria and yeast)

Nucleotides

Biomolecules that play an important role in energy and info transfer

What are the 3 basic structures of a nucleotide?

1) ATP (adenosine triphosphate)

2) ADP (adenosine diphosphate)

3) Cyclic AMP

What are the two main groups of nitrogen-containing base molecules?

Purines (have a double ring structure)

Pyrimidines (have a single ring)

What are the specific nitrogen containing bases, and what group do they belong in?

1) Adenine (A) -> Purines

2) Guanine (G) -> Purines

3) Cytosine (C) -> Pyrimidines

4) Thymine (T) -> Pyrimidines

5) Uracil (U) -> Pyrimidines

Polymers

Large molecules made up of repeating units

True lipids consist of...

glycerol and fatty acids

What determines the type of true lipid a molecule is?

The number of fatty acids

How many tails are in a monoglyceride (lipids)?

one

How many tails are in a disaccharide (lipids)?

two

How many tails are in a triglyceride (lipids)?

three

What is the most prevalent form of true lipids in the human body?

Cholesterol

Describe the glycerol subunit

Glycerol is a simple 3-carbon molecule that makes up the back bone of most lipids

Describe the fatty acid subunit

Long chains of carbon atoms bound to hydrogens with a carboxyl (-COOH) or "acid" group at one end of the chain

Saturated fatty acids

No double bonds between carbons, so they are "saturated" with hydrogens. More fatty acids = more likely to be solid at room temp

Unsaturated fatty acids

Have one or more double bonds between carbons in the chain

Phospholipids

Cholesterol and phospholipids are important components of animal cell membranes

Steroids

Cholesterol is the primary source of steroids in the human body

Eicosanoids

Act as regulators of physiological functions

Proteins

Structural (insoluble) or functional (soluble) molecules consisting of amino acids

Carboxyl group

Gives the molecule an acidic quality

The "R" group

A group of atoms that determines which of the 20 amino acids this one is

The amino group

A functional group typically associated with proteins

Proteins form chains by...

being bonded together at a peptide bond (amino group of one amino acid to the carboxyl of the next amino acid)

Amino acid-based molecules are categorized by...

the number of amino acids in the strand

Oligopeptides (# in a strand)

2-9 amino acids

Peptides (# in a strand)

10-100 amino acids

Proteins (# in a strand)

100+ amino acids

What are the four levels of protein structures?

1) Primary

2) Secondary

3) Tertiary

4) Quaternary

Primary

Genetically determined sequence of amino acids

Secondary

Spatial arrangement of amino acids in the strand

Secondary spatial arrangement determined by...

the best fit between R groups of individual amino acids in the strand

Secondary forms

Either alpha helices (spiral shapes), or beta pleated sheets (accordion folded sheets)

Tertiary

3D arrangement of alpha helices and beta pleated sheets

Tertiary forms

Either globular (ball-like) or fibrous (strand-like) shapes