Biol 186 final

Physiology

The study of the functions of organisms - whole of natural history/natural science.

Anatomy

The study of the structure of organisms.

Functional anatomy

function correlates with structure in the tissue of animals.

Tissue

integrated group of cells with common structure and function.

Epithelial tissue

tightly packed sheet of cells that covers body, organs, and cavities. polarized with apical and basal surfaces.

function of epithelial tissue

barrier, exchange surface, absorption or secretion of chemical solutions.

types of epithelial tissue

simple, stratified, pseudostratified, cuboidal, columnar, and squamous.

connective tissue

few cells with extracellular matrix.

function of connective tissue

bind and support other tissue.

loose connective tissue

all 3 fibre types - packing material - fibroblasts and macrophages.

connective tissue fibres

collagenous, elastic, and reticular.

fibrous connective tissue

collagenous fibres - tendons and ligaments - non-elastic strength.

adipose connective tissue

stores fat, pads, and insulates - specialized loose connective tissue.

cartilage connective tissue

flexible support, abundance of collagenous fibres in rubbery matrix - chondrocytes.

bone connective tissue

skeleton supporting body with mineralized connective tissue - calcium, magnesium, phosphate ions - osteoblasts and osteocytes.

blood connective tissue

extensive extracellular matrix which is liquid plasma - erythrocytes, leukocytes, platelets.

muscle tissue function

fibres contract when stimulated by nerve impulses.

types of muscle tissue

striated (voluntary movements), smooth (intestines), cardiac.

nervous tissue function

sense stimuli and transmit signals from one part of the animal to another.

nervous tissue cells

neurons: functional units of nervous tissue that transmit nerve impulses.

glia: support neurons metabolically, structurally, and functionally.

organs

specialized centre of body function composed of several different types of tissues.

organ system

group of organs that work together in performing vital body functions.

signalling by hormones

slow, long-lasting, limited to cells with receptor for that signal, involves endocrine system and is transmitted via bloodstream.

signalling by neurons

very fast, brief signal through nervous system

limited to cells that are connected by specialized junctions and, if chemical synapse, have receptor for neurotransmitter.

mechanisms of homeostasis

interstitial fluid and homeostasis.

osmoconformer

animal that does not actively adjust its internal osmolarity because it is isosmotic with its environment.

invertebrates.

osmoregulator

animal whose body fluid has a different osmolarity than that of the environment

hypoosmotic: must discharge excess water.

hyperosmotic: must take in extra water.

vertebrates.

stenohaline

organisms that cannot tolerate substantial changes in external osmolarity.

euryhaline

organisms that can tolerate substantial changes in external osmolarity.

transport epithelium

layer of specialized cells that regulate solute movements.

have ability to move specific solutes in controlled amounts in particular directions.

cells are joined by tight junctions.

arranged in tubular networks with extensive surface area in most animals.

anhydrobiosis

ability to survive in a dormant state when an organism’s habitat dries up.

components of homeostatic systems

sensory: perceives change.

integrator: compares sensor’s input with internal set-point.

effector: brings about response.

negative feedback

change in variable triggers control mechanisms and counteracts further change.

positive feedback

change in variable triggers mechanisms and amplifies change.

alternations in homeostatis

regulated changes: essential to normal functions - hormone shift.

circadian rhythm.

acclimation: physiological adjustment to a change in a single environmental factor.

acclimatization: physiological adjustment to changes in complex environmental factors.

conduction

direct transfer of thermal motion between molecules of objects in direct contact with each other.

convection

mass movement of warmed air or liquid to or from the surface of a body or object.

radiation

emission of electromagnetic waves by all objects warmer than absolute zero.

evaporation

removal of heat energy from surface of a liquid that is loosing some of its molecules.

ectotherm

environment determines body temperature.

restricted geographically, limited energy bursts.

lower metabolic rates, smaller body mass.

adjusts to changing temperature and seasons at cellular level, production of cryoprotectants.

endotherm

animal generates internal heat to maintain body temperature.

requires lots of food and water because high metabolism.

can sustain long periods of intense activity.

vasodilation

increase diameter of superficial blood vessels to elevate blood flow in skin which triggers nerve signals that relax muscles of vessel walls. This increases transfer of body heat to cool environment.

vasoconstriction

decrease diameter of superficial vessels which reduces blood flow and heat transfer.

countercurrent heat exchanger

special arrangement in blood vessels facilitates heat transfer from arteries to veins and helps trap heat in body core.

high basal metabolic rate

production of large amounts of metabolic heat that replace flow of heat to environment.

cooling by evaporative heat loss

sweating, panting, and mucus secretion.

behavioural responses

change position, move in environment.

shivering thermogenesis

increased muscle activity produces more heat.

non-shivering thermogenesis

increases metabolic rate due to hormonal changes.

mitochondrial activity produces heat instead of ATP.

Brown fat specialized for rapid heat production.

feedback mechanisms in mammals for temperature

neurons in hypothalamus function as thermostat.

sensory cells signal hypothalamus when temperature increases or decreases.

hypothalamus responds by activating or inhibiting appropriate mechanisms.

metabolic rate

amount of energy an animal uses in a unit of time; sum of all energy-requiring biochemical reactions occurring over a given time interval.

basal metabolic rate

stable rate of energy metabolism measured in mammals and birds under conditions of minimum environmental and physiological stress.

standard metabolic rate

measure that is similar to BMR but used for animals with varying body temperature that is maintained at selected body temperature.

torpor

physiological state in which activity is low and metabolism decreases.

estivation

summer torpor.

components of circulatory system

pump, vessels, circulatory fluid.

functions of the circulatory system

maintenance of homeostasis.

mass transport of solutes and cells.

transport of heat.

transmission of force.

cardiac output =

heart rate times stroke volume

cardiac cycle

one complete sequence of pumping and filling.

systole

heart muscle contracts and chambers pump blood.

diastole

heart muscle relaxes and chambers fill with blood.

ECG

1. signals from SA node spread through atria.
2. signals are delayed at AV node (gives time for ventricles to fill with blood before signal for ventricular contraction is passed along).
3. bundle branches pass signals to heart apex.
4. signals spread throughout ventricles.

artery

carries oxygenated blood away from the heart and towards the capillaries.

pulmonary artery is exception because it carries **deoxygenated** blood away from heart to lungs.

veins

carries deoxygenated blood toward heart from capillaries.

pulmonary vein is exception because it carries **oxygenated** blood toward heart from lungs.

function of the lymphatic system

fluid balance: there’s a net leakage of fluid and proteins from blood capillaries - lymph capillaries collect lost fluids and return to blood circulation.

defense: lymph nodes have defense cells.

lymph capillaries pick up fats absorbed by small intestine and transfer it to blood.

fluid movement of the lymphatic system

one way valves, moved by contraction of skeletal muscles.

lymph circulates in an open system.

thymus

site of maturation of T lymphocytes.

tonsils

handle infections in the mouth.

function of the spleen

defense, red blood cell destruction, blood reservoir.

origin of cellular elements in blood

pluripotent stem cells in bone marrow.

leukocytes

very small, defense and immunity.

erythrocytes

responsible for O2 and CO2 transport.

bigger.

contain: hemoglobin, spectrin (membrane skeleton), glycolytic enzymes, carbonic anhydrase.

erythropoiesis

formation of erythrocytes.

starts in bone marrow and completed in circulated blood.

initiated when tissues don’t receive enough oxygen.

normally balanced with destruction.

platelets

small, short-lived fragments of cells that are activated by exposed collagen fibres in damaged tissue of vessel wall, foreign surfaces, and thrombin.

they release clotting factors and change shape upon activation.

prothrombin

circulated in plasma.

prothrombin turns into thrombin turns into fibrinogen turns into fibrin.

opposing clotting

anticlotting agents = heparin.

fibrinolysis

dissolution of fibrin and thrombus (clot dissolution).

plasmin (enzyme) - produced in inactive form (plasminogen) in liver.

clot lysis: complex process involving proteolytic enzymes, activators, and inhibitors of plasmin and other proteases.

low-density lipoproteins

deliver cholesterol to cells for membrane production.

high-density lipoproteins

scavenge excess cholesterol for return to liver.

atherosclerosis

thickening or hardening of the arteries caused by buildup of fatty deposits of plaque.

gills

internal or external vascularized membranes, ventilated by flow of water over them, oxygen diffusion aided by countercurrent exchange.

tracheal system

internal network of air tubes, cells supplied directly, system can be ventilated by body movements, which compress and expand tracheoles.

lungs

localized respiratory organs, subdivides infolding of body surface.

bird lungs

inflatable air sacs associated with rigid lungs.

human respiratory system

lungs, trachea, bronchi, alveoli.

alveoli

site of gas exchange due to thin epithelium - lined by film of water with surfactant that reduces surface tension.

inhalation

diaphragm contracts and move down - rib cage expands as rib muscles contract.

hemocyanin

special protein that transport oxygen in blood - oxygen binds to copper.

in arthropods and many molluscs.

hemoglobin

oxygen binds to iron

in red blood cells - four subunits

bisphosphoglycerate

important regulator for affinity of hemoglobin for oxygen.

bohr shift

drop in pH lowers affinity of hemoglobin for oxygen.

binding of oxygen to one hemoglobin subunit

changes shape of other subunits so that the affinity for oxygen increases (same with release of one oxygen).

dalton’s law

in a mixture of gases, the total pressure is the sum of the pressure each gas would exert if it were present alone.

oxygen exchange between tissues and blood

diffuses down PO2 gradient (partial pressure - amount dissolved in blood).

from alveolar spaces into lung capillaries.

from systemic capillaries to tissues.

carbon dioxide exchange between tissues and blood

diffused down PCO2 gradient.

from tissues to systemic capillaries and from lung capillaries to alveolar spaces.

sensation

triggered by sensory stimuli

travel to brain as action potentials via sensory pathways.

functions of the nervous system

rapid communication and information processing (sensory input, integration, motor output).

afferent neurons

from periphery to central nervous system

efferent neurons

from central nervous system to periphery.

chemoreceptor

senses change in chemical composition of blood.