BIOSC-130 Exam 5: Key Biology Terms & Definitions

Types of Body Plans

- single-celled

- simple multicellular

- complex multicellular

Single-celled body plan

direct exchange with environment ex. amoeba

simple multicellular body plan

most cells contact environment ex. hydra

gastrovascular cavity

enables exchange of internal cell layer in simple body plan

complex body plan

exchange surfaces with internal fluids (interstitial and circulatory fluids)

Interstitial Fluid

fluid in the spaces between cells; buffers cells

Circulatory Fluid

moves material throughout body ex. blood

Cardiovascular System

transport system of the body responsible for carrying oxygen and nutrients to the body and carrying away carbon dioxide and other wastes

Components of Cardiovascular System

- pump = heart

- tubes = vessels

- fluid = open (hemolymph); closed (blood)

Open Circulatory System

fluids called hemolymph bathes the organs, equivalent to interstitial fluid. ex. cricket

Closed Circulatory System

circulatory system in which the oxygen-carrying blood cells never leave the blood vessels; interstitial and circulatory fluids kept separate

Heart Chambers

atria and ventricles

Atria

upper chambers of the heart that receive bloods from veins

Ventricles

lower chambers of the heart that pump blood to arteries

Valves

Flaps of tissue that open and close to allow the flow of blood in one direction only

atrioventricular valves

valves located between atrium and ventricles

semilunar valves

valves located between the ventricles and arteries

Pulmonary Circuit

carries blood to the lungs from right heart for gas exchange and returns it to the left heart --> oxygenates blood

Systemic Circuit

carries blood between the left heart towards the body and back to the right heart --> delivers oxygenated blood to body

Cardiac Cycle

A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles

Step 1 of Cardiac Cycle

atrial, ventricular diastole --> relaxed heart lets blood into atria and ventricles

Step 2 of Cardiac Cycle

atrial systole, ventricular diastole --> atria contracts to push blood into ventricles

Steps 3 of Cardiac Cycle

atrial diastole and ventricular systole --> ventricles contacts to push blood from ventricles to arteries, atria relax to let blood flow from veins into atria

diastole

relaxation of heart that allows blood to fill

systole

contraction of heart muscles to pump blood

Cardiac Output

volume of blood ejected from the left side of the heart in one minute

Stroke volume

The amount of blood ejected from the heart in one contraction (mL/beat)

Heart Rate

number of beats per minute

Cardiac Output Formula

CO = SV * HR

Resting Cardiac Output

70mL/beat * 70 beats/min = 4900 mL/min

Heart Sounds

"lub" = AV valves close --> ventricular systole closes AV valves

"dub" = SL valves close --> ventricular diastole, aterial pressure closes SL valves

Sinoatrial (SA) Node

the pacemaker; highly specialized, neurological tissue impeded in the wall of the right atrium; responsible for initiating electrical conduction of the heartbeat, causing the atria to contract and firing conduction of impulses to the AV node

SA Node Regulators

- autonomic nervous system = sympathetic increase; parasympathetic decrease

- hormones = epinephrine

- body temperature

Electrical Conduction in Heart

SA node --> atria, AV node, fibers (bundle branches) --> apex (bottom), ventricles

Blood Flow

arteries --> arterioles --> capillaries --> venules --> veins

Arteries

deliver blood away from the heart

- stores systolic pressure --> slowly release

- maintains driving pressure during relaxation (diastole)

Arterioles

direct blood flow

- change diameter (vasoconstriction and vasodilation) --> resistance --> impacts blood pressure and directs flow

Vasoconstriction

Narrowing or constricting of blood vessels decreases blood flow to vessels

Vasodilation

widening of blood vessels increases blood flow to vessels

Capillaries

Microscopic vessel through which exchanges take place between the blood and cells of the body

What is capillary flow controlled by?

- arteriole diameter/vasoconstriction/vasodilation

- precapillary sphincters that adjust flow into capillaries

Characteristics of capillaries

- narrow and numerous --> large surface area that decrease blood velocity and increase exchange

- thin, porous walls good for exchange

- no muscles

Capillary Exchange

large molecules (cells/proteins) --> most stay in blood/plasma, small number move via exo/endocytosis

small molecules (gases, ions, nutrients) --> through cells/diffusion/membrane transport; around cells via pores in capillary walls

Capillary Exchange Pt. 2

fluids move through pores in capillary walls

- filtration (OUT): circulatory --> interstitial due to blood pressure

- reabsorption (IN): interstitial --> circulatory due to osmotic pressure pulls proteins back in

How fluids are returned into circulatory system

if filtration > absorption --> net loss of fluid. fluids collected and returned by lymphatic system

What is the impact of capillary porosity on blood pressure?

reduces blood pressure

Venules/veins

return blood to the heart that have one-way valves to ensure unidirectional flow

Venous Return

volume of blood returned to the heart hindered by gravity

How is blood aided in returning despite gravity?

- muscles in walls of veins (venoconstriction)

- peripheral pumps (skeletal and respiratory)

- diastolic suction

Starling's Law of the Heart

"pump what you get" --> influences stroke volume, cardiac output

Arteriosclerosis

"hardening of the arteries" due to lipid deposits/plaques that reduce elasticity --> narrow arteries and reduce flow --> heart attack when there is a blockage

Myocardial Infraction

"heart attack" due to blockage in coronary artery due to blood clot causing inadequate O2 to cardiac muscle that damages cardiac muscle

Treatments for Heart Attack

bypass surgery, stent, stem cells

Parts of the Respiratory System

upper = mouth, nasal cavity, pharynx, larynx (conditions air and provides protection)

lower = trachea, bronchi, bronchioles, alveoli (exchange due to big surface area)

What drives breathing?

negative pressure breathing

- inhale = Pout > Pin, air moves in

- exhale = Pin > Pout, air pushed out

Tidal Volume

normal breath

Vital capacity

maximum inhale, maximum exhale

Residual volume

air remaining following exhale --> "used air mixes with "new" air

How does altitude impact breathing?

Altitude reduces pressure differences --> slows diffusion

What drives partial pressure gradients?

drives O2 from lungs into tissues and CO2 from tissues into lungs

Partial Pressure

Pgas = Ptotal *%gas

Hemoglobin (Hb)

tetramer protein in red blood cells that reversibly binds O2 in blood stream --> four O2 per Hb --> binding at one site influences binding at others

How does carbon dioxide influence Hb and O2 affinity?

increased CO2 production lowers pH, induces increased O2 release from Hb --> increased metabolic activity matched in increased O2 delivery

forms of CO2 transport

hemoglobin = Hb

plasma = 7%

bicarbonate = 70%

What are our bodies "lines of defense"?

- physical barriers = block entry

- internal innate responses = rapid, broad specificity

- adaptive immunity = slower, highly specific, develop through life

Two Major Branches of Immune System

Innate and adaptive immunity

Innate immunity

Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens.

Adaptive immunity

the ability to recognize and remember specific antigens and mount an attack on them

Surface Barriers

- skin

- mucous membranes (trap = mucous; inactive and wash away = tears, saliva; create hostile enviro = low pH of stomach, urinary tract, and skin)

- commensal bacteria

Leukocyte

white blood cells, which protect the body against disease

Innate Immune Responses

- First line of defense

(Fast, but nonspecific)

- Cellular and non-cellular innate defenses

Cellular Innate Defenses

- toll-like receptors (TLRs)

- phagocytosis (neutrophils, macrophages)

- targeted death of infected host cells (natural killer cells/lymphocytes)

Non-cellular Innate Defenses

- complement proteins (membrane attack complexes)

- anti-microbial peptides

Inflammatory Response

nonspecific defense reaction to tissue damage caused by injury or infection

Histamine

increased blood flow (vasodilation), makes capillaries more leaky

Cytokines

attract/activate other immune cells

Lymphocytes

type of white blood cell that make antibodies to fight off infections

B-cells

cells manufactured in the bone marrow that create antibodies (antibody-mediated response) for isolating and destroying invading bacteria and viruses in blood --> antigen interaction stimulates antibody production

Humoral response

antibodies defend against infection in body fluids

T-cells

Cells created in the thymus that produce substances that attack infected cells in the body --> requires host cell presentation of antigen that is presented in MHC molecule

Antigen

any molecule that elicits a response from B or T cells using epitopes

Epitopes

portion of antigen that binds the antigen receptor (receptor epitopes per antigen)

How is receptor diversity possible?

during development, segments of receptor genes are combined randomly (Pick 1 V, 1 J, add C, and combine)

Self-tolerance

the body lacks mature lymphocytes that can react against its own components

Autoimmune disease

immune system attacks self

clonal selection

antigens bind to specific receptors, causing a fraction of lymphocytes to clone themselves

Step 1 of Clonal Selection

selection

Step 2 of Clonal Selection

clonal expansion

- mitosis

Step 3 of Clonal Selection

Differentiation

- effector cells = immediate action short-lived

- memory cells = persist for subsequent exposure

Antibody mechanisms of action

- neutralize pathogen directly

- facilitate phagocytosis

- activate other defenses

What are allergies?

exaggerated responses to antigen

MHC molecule

major histocompability complex

What is required to activate T-cells?

simulatenous interaction with antigen (via antigen receptor) and MHC molecule

What do activated T-cells release?

chemical to kill infected host cell (perforins that makes pores, granzymes which induce suicide)

Cytotoxic T-cell

activator = infected somatic cell

receptor = MHC-1

Helper T-Cell

activator = antigen-presenting WBC (dendritic cell, macrophage, B-cell)

receptor = MHC-2

What is unique about helper T-cells?

activates both branches of adaptive immune response (humoral and cell-mediated)

Active immunity

defenses derived from response to infection

- vaccination

Memory cells

B lymphocytes that do not become plasma cells but remain dormant until reactivated by the same antigen

Passive immunity

the short-term immunity that results from the introduction of antibodies from another person or animal.