PHYSIOLOGICAL CHEMISTRY AND PROCESSES Flashcards
1
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ANATOM, MOLECULES AND COMPOUNDS
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- element = substance containing one type of atom
- susbtance = two/more atoms = compounds
- water = compound (hydrogen & o2)
- 92 natrual elements
- Compounds make up living tissues
- carbon, hydrogen, o2 & nitrogen
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Q
ATOMIC STRUCTURE
proton = 1 unit = 1 Positive
Neutron = 1 unit = 1 neutral
Electron = negligible = 1 negative
A
- atoms = space, central nucleus
- contain protons (positive charge) & neutrons (no electrical charge) surrounding orbiting electrons (negatively charged)
- atoms contain an equal number of proton &electrons
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Q
ATOMIC NUMBER AND ATOMIC WEIGHT
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- 1 element is different due to the number of protons in the nucleus of its atoms
- elements have their unique atomic number
- the atomic weight of an element = sum of protons and neutrons in the atomic nucleus
- orbit in concentric rings around the nucleus
- shells represent different energy levels of atom electrons
- first level = 2 electrons
- second level = 8 electrons
- third level = up to 18 electrons
- when the outer shell doesn’t contain a stable number, they donate, receive/share electrons = achieve stability
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Q
ISOTPES
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- atoms of an element = different number of neutrons in the nucleus
- doesn’t affect the electrical activity
- it does affect their atomic weight
- The most common isotope has 1 proton in the nucleus & orbiting the electron
- some isotopes = unstable these extra neurons
- achieve a more stable state by emitting radiation detected by the Geiger counter
- radioactive isotopes = radioisotopes
- radiation that it emits = used to kill cancer, injected into the bloodstream = obstructions/abnormalities
- attacking hollow passageways and organs
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Q
MOLECULES AND COUMPOUNDS
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- When the number of electrons in the other shell of an element is either at max number/stable = inert / chemically unreactive
- doesn’t readily combine with other atoms
- molecules consist of 2/more atoms that are chemically combined
- Most molecules are compounds and contain 2/more different elements
- compounds containing carbon and hydrogen = organic others are inorganic
- body requires inorganic compounds
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Q
COVALENT AND IONIC BONDS
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- chemical processes are entirely dependent on the way atoms are combined into molecules = broken down into constituent atoms
- Ionic bonds are weaker than covalent bonds and form when electrons are transferred from one atom to another
- ionic bonds are weaker than covalent bonds and form when electrons are transferred from one atom to another charges carried by an ion are indicated by the superscript +/- signs, i.e sodium ion (Na+) carries an additional +ve charge
- calcium ion (Ca2+)
- most ionic compounds dissolve well in water, releasing their charged ions into the soultions = electrolytes
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Q
ELECTROLYTES
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- allows to conduct electricity
- permit generation & conduction of action potential, electrical signals for muscles and nerve function
- osmotic pressure keeps body fluids inside the body
- acts as a buffer that resists pH changes in body fluids
- Many biological compounds - not ionic = no electronic properties when dissolved in waters
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Q
MEASUREMENT OF SUBSTANCES IN BODY FLUIDS
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- units used are based on weight in grams/fractions of a gram
- if the molecular weight of a substance is concentrated = moles,
- sometimes the substance = terms of activity, i.e. insulin measured in international units (IU)
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Q
ACIDS, BASES & pH
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- fluid = pH = indicator of its acidity/alkalinity
- living cells are sensitive to change
- biochemical continuously produces hydrogen ions in solutions
- Homeostatic mechanisms in the body regulate and monitor the pH
- Basic (alkaline) substance = hydrogen ions = hydroxyl (OH-)
- Neutral substance, e.g. water release = concentration H+ and OH-
- salt release anions & cations when dissolved = sodium chloride = solution release sodium and chloride ions
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Q
THE pH SCALE
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- standard scale = measurements - hydrogen
- the scale measurement 0-14, 7 as the midpoint = neutral, i.e. water
- pH below = acid solution, pH above = alkaline solutions
- The solution of pH 5 contains 10 times as many hydrogen ions as the solution of pH 6
- strong acids dissociate more extensively than weak acids
- not all bases dissociate completely.
- strong bases dissociate more fully
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Q
pH VALUES OF BODY FLUIDS
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- pH of body fluids maintained within narrow limits
- most body fluids = close to neutral
- highly acid pH = gastric juice maintained by hydrochloric acid secreted by parental cells in the wall of the gastric glands
- low pH destroys microbes & toxins swallowed by food/drink
- blood pH is 7.35 & 7.45, outside of a small range of severe disruption to normal physiology & biochemical processes
- metabolic activity body cells = acids & bases = alter the pH of tissue, fluid & blood
- chemical buffer binds hydrogen ions, responsible for keeping body pH stable
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Q
BUFFERS
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- body pH is kept stable by systems of buffering chemicals in body tissues & tissue
- buffering mechanisms = homeostatic mechanisms = temp neutralised fluctuations in excess acid/bases = excreted from the body.
- lungs essential regulators of blood pH = excrete CO2 increases (H+) body fluids combines with water to form carbonic acid
- bicarbonate = good buffer = combines with & neutralises excess H+ ions
LUNGS: - control blood excrete excess CO2
- The brain detects a rise in H+ in blood, stimulates breathing, and increases CO2 loss in the air.
- Blood pH = too essential brain can reduce the resp rate to increase CO2 levels & increase (H+) decreasing pH towards normal
KIDNEYS: - regulate blood pH = adjusting excretion of hydrogen & bicarbonate ions = required
- If pH falls = (more acidic) H+ excretion increased = reverse happens if pH rises
- buffer systems = body protein
- haemoglobin = red blood cells absorb excess H+ & phosphate
- body maintains the acid-base balance so that the pH range of body fluids remains within normal limits
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Q
ACIDOSIS & ALKALOSIS
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- buffer system = compensates for most pH fluctuations, reserves = limited, could lead to exhausted
If the pH falls below 7.35, all reserve alkaline buffers will be 7.45; the increase in alkali will cause the acid buffer to be used up, and alkalosis will develop. If the pH rises above. - Acidosis & Alkalosis = dangerous for central nervous system & cardiovascular system
- Acidic conditions = more common than alkalotic = metabolic processes of the body tend to produce more acid than alkali
- respiration problems, if lungs don’t excrete CO2 efficiently/body, produce excessive acids
- kidney disease if renal H+ excretion = reduced
- Alkalosis = loss of acidic substances through D&V
- increased respiratory effort = anxiety attacks where excessive amount of CO2 are lost through hyperventilation
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15
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CARBOHYDRATES
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- contain carbon, O2 and H (ratio 1:1:2)
- O2 & H ( linked togehter)
- when two sugar molecules combine to make a bigger molecule = glycosidic linkage
- glucose cell = fuel molecules monosaccharide (mono = one) (saccharide = sugar)
- long chain contains thousands of monosaccharides = starch
- Glucose can be broken down either in the presence (aerobically)/absence (anaerobically) of O2
- energy, water, and CO2 released in constant supply = glucose = cellular metabolism
- blood glucose level = controlled
FUNCTIONS OF SUGARS: - Source energy fuels cellular metabolism
- energy store
- forms part of DNA & RNA
- acts as receptors on the cell surface
- binds to them biologically, i.e. neurotransmitters, hormones
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Q
AMINO ACIDS & PROTEINS
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- cotain O2, H, carbon & nitrgen
- traces of sulphur, magnesium, phosphate
- 20 amino acids used as principal building blocks of protein
- acid used in specific proteins and some found in microbe products
- glycoside linage two amino acids combine with water molecules = peptide bond
- protein amino acids linked together
- protein and carbs chains have a wide range of functions = cell biology (cell surface markers, receptors).`
- changes in pH = damaging to living cells = hydrogen ions = internal structures change the shape of the protein (denaturing it) = unable to function
- carrier molecules
- enzymes
- hormones
- antibodies
- protein = alternative energy in starvation
- the primary source of body protein muscle tissue, muscle wasting = feature of starvation
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Q
LIPIDS
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- unable to mix with water (hydrophobic)
- contain: carbon, H, O2
- FATS (triglycerides) stored in adipose tissue (energy source)
- FAT: insulates the body, protects the internal organs
- FAT: broken down to optimal conditions = energy released glucose = fully broken down
- saturated/unsaturated depends on the chemical nature
- SATURATED: fat = solid, UNSATURATED: FAT = oils
- Phosphliphates = cell membrane structure (double layers, water repellent)
- vitamins: fat-soluble vitamins (A, D, E & K)
- Prostaglandins = chemically divided fatty acids, inflammation and other processes
- steroid hormones sex steroids by gonads (ovaries & testes)
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Q
NUCLEIC ACIDS
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- most significant molecules in the body
- include DNA & RNA
19
Q
ADENOSINE TRIPHOSPHATE (ATP)
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- nucleotide containing ribose (sugar), adenine (the base)
- called the energy current of the body
- body ‘earns’ (synthesis) it before ‘spend’ it
- mitochondria = ATP organelles
- release energy = break down sugar with O2, mitochondria enzyme capture energy, forming adenosine diphosphate (ADP)
- chemical energy = fuels metabolic activities, and ATP is broken down to ADP, releasing water.
- energy generated, APT breakdown fuels muscle contraction, mobility of the spermatozoa, anabolic reactions
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Q
ENZYMES
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- chemical reactions
- Enzymes = protein acts as catalysts for biochemical purpose
- speed up the reaction, but don’t themselves change by it are used over again
- molecules entering the reaction = substrate binds to spefic area on enzyme = active site
- enzyme reaction = reduced/stopped altogether if unstable. increased/decreased temp = reduce activity
- enzyme catalysts, both synthetic (anabolic)/breakdown (catabolic) reaction
- catabolic reactions = breakdown of substrate = smaller products = during digestion of food in gastrointestinal tract = absorption take place
- external environment = collection of physical & chemcial & biological conditions external to living organisms
- internal enviroment = water base.
- cells bathed in fluid = interstital / tissue fluid = absorbing oxygen and nutrient = excreating into waste `
- circulating blood, supplies O2 and nutrients and absorbs & carries away waste.
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Q
HOMEOSTASIS (unchanging)
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- internal environment = tightly controlled
- physiological mechanisms & measurements adjusting within the limits
- balance = threatened/lost = serious risk of well-being to the individual
- physiological variables maintained within narrow limits by homeostatic control mechanism
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Q
CONTROL SYSTEMS
A
- homeostasis = control system detect & respond to changes = internal environment
- control system: sensor (detector), control centre (determines limits) & effector (maintained receives and integrates information from control centre)
- control centre: responds to changes in its output effector
- dynamic process = constant flexibility and readjustment of physiological
- nearly all controlled by negative feedback
- positive feedback = blood clotting
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Q
NEGATIVE FEEDBACK MECAHNISMS
A
- movement of a control system away from its standard set point = reversing
- variable rise = -ve feedback bringing it down again (bring it down to a normal level)
- response to change
- keeps systems in a steady state and maintains homeostasis (body temp)
- preset maximum temp is reached = system reversed
- continuous self-regulation, control
- detected by temp-sensitive nerves, mainly in the skin
- relay info to the control centre = hympthamulus
- hympthamulus activates mechanisms
- stimulation of skeletal muscles = shivering
- constrictions of blood vessels in skin = heat loss through the skin
- behavioural changes = putting on more layers
- body temp within normal range temp-sensitive nerve ending no longer stimulated = stop hympthamus = shivering stops, blood comes back to the skin
- homoestastic control = -ve feedback to prevent sudden changes = serious changes to the internal enviorment = disease
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Q
POSITIVE FEEDBACK MECHANISMS
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- progressive response
- stimulus is continuous, the response is progressively amplified = blood clotting
- the uterus is stimulated = oxytocin forcing the baby’s head - cervix, stretch receptors = more oxycontin
- after the baby is stimulated (stretching of the cervix), no longer present, releasing oxytocin stops
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HOMEOSTATIC IMBALANCE
- the system is excessive
- happens rapidly = may not adopt
- the system may shift outside of the normal physiological range
- leading = disruption/disease = corrected
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MOVEMENT OF SUBSTANCE WITHIN BODY FLUIDS
- distribute from a high concentration to an area of low concentration
- no barriers in the way
- concentration gradient = high concentration to low concentration
- the movement of substance - happens down(hill) until even distribution
- no energy is used in the process
- movement of substances across cell membranes = active transport
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DIFFUSION
- the movement of molecules = high concentration - low concentration (gases, liquids & solutions)
- through diffusion speeded up temp rises concentrtation of diffusing substance is increased
- semipermeable membrane = capillary wall - only molecules small/soluble enough to cross.
- membrane can diffuse through
- O2 concentrations are high
- think walls of blood capillaries in the bloodstream in the bloodstream = low concentration of O2
- plasma too large to cross and maintain in the blood
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OSMOSIS
- semipermeable membrane (SM) - equal concentration on both sides of the membrane
- diffusion of water down a concentration gradient through an SM
- molecules = too large to pass through pores in the membrane = osmosis pressure = pulls water from the dilute solution
- osmosis blood pressure = equilibrium reached = each side of the membrane = same concentration = isotonic
- control solute concentrations in body fluids, illustrating looking at the cell
- expose the solution differs from normal physiological
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FLUID COMPARTMENTS
- water in body = 60% adults
- 40 litres of the body
- INTERCELLULAR FLUIDS: fluid inside the body cells,
- EXTRACELLULAR FLUIDS: fluid found outside the cells
- water is a small cell exchange freely cell membranes
- specific transport mechanisms = movement controlled
- water = intercellular 70%, extracelluar 30%
- 22% body weight extracellular, 32% intercellular water
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EXTRACEULLUALR FLUIDS
- blood, plasma, lymph, cerebrospinal fluid
- Main role in lubrication Joint (synovial), pericardial fluids (around the heart)
- interstitial fluid substances diffuse from blood to body cells and cells from the blood
- Even slight changes = permeant damage
- rising blood potassium means interfering with cardiac functions = the heart stops beating
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INTERCELLULAR FLUIDS
- controlled by the cells themselves
- water concentration in ICF & ECF
- The concentration difference occurs because sodium diffuses cells down its concentration gradient pumped into the membrane
- This concentration gradient is essential for the function of excitable cells, mainly nerve and muscles
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