exchange and transport Flashcards
alveoli
tiny air sacs that serve as the primary gaseous exchange surface
consist of thin epithelial cell layer, collagen and elastic fibres
breathing rate
number of breaths per minute
bronchi
divisions of the trachea that lead into the lungs
small tubes supported by incomplete rings of cartilage
bronchioles
many small division of the bronchi
contain smooth muscle to restrict airflow to the lungs but do not have cartilage
lined with a thin layer of ciliated epithelial cells
cartilage
strong, flexible connective tissue that supports the walls of the trachea and bronchi, preventing collapse
it is found in an incomplete ring shape
ciliated epithelial cells
specialised cells with tiny hair-like cilia found lining the trachea
waft bacteria containing mucus up to back of the throat, where it is swallowed
counter current flow
an adapation for gaseous exchange in bony fish
blood in the gill filaments and water moving over the gills flow in opposite directions
maintains a steep oxygen concentration gradient
elastic fibres
fibres of elastin that allow the alveoli to stretch as air is drawn in and recoil back to normal size, expelling air
also found in the trachea, bronchi and bronchioles
exchange surface
a surface where materials are exchanged from one region to another
an effective exchange surface has a large surface area, thin layers, a good blood supply and ventilation to maintain a steep diffusion gradient
expiration
exhalation
diaphragm relaxes and reverts to a dome
the external intercostal muscles relax, moving ribs down and in
the volume of the thorax decreases and thoracic pressure exceeds air pressure
air moves out of the trachea
gill filaments
main site of gaseous exchange in fish, over which water flows
they are found in large stacks (gill plates)
have gill lamellae - provide a large surface area for exchange
gill lamellae
the fine branches of the gill filaments
are adapted for gaseous exchange by having a large surface area and good blood supply
gill plates
large stacks of gill filaments
gills
organs of gaseous exchange in fish
contained in a gill cavity and are made up of gill lamellae, gill filaments and gill plates
goblet cells
specialised cells that secrete mucus onto the trachea lining
mucus traps harmful substances and microorganisms, preventing their entry into the lungs
inspiration
inhalation
diaphragm contracts and flattens
the external intercostal muscles contract
moving the ribs up and out
volume of the thorax increases
thoracic pressure falls below air pressure
air moves into the trachea
internal intercostal muscle
muscles found between the ribs which are responsible for forced exhalation
mammalian gaseous exchange system
a complex system found in mammals in which oxygen and carbon dioxide gases are exchanged
operculum
a flap that covers the gills of bony fish
it protects the gills and helps to maintain a constant stream of water over them
smooth muscle
an involuntary muscle found in the walls of the trachea and bronchi
it constricts the lumen of the bronchi by contracting, reducing airflow to the lungs
spiracles
small, external openings along the thorax and abdomen of most insects
air enters and air and water leaves the gaseous exchange system
spiracle sphincters open and close the spiracles to control gas exchange
spirometer
a device used to examine patterns of breathing
determine different aspects of lung volume
tidal volume
the volume of air that moves into and out of the lungs during a normal breath
trachea (mammals)
the primary airway which carries air from the nasal cavity down into the chest
a tube supported by incomplete rings of cartilage
tracheae (insects)
large tubes that run from the spiracles, into and along an insect’s body
supported by spirals of chitin
the tracheae divide further into smaller tracheoles
tracheal fluid
a fluid found at the ends of the tracheoles
amount of fluid affects the surface area available for gaseous exchange and water loss
tracheoles
divisions of the tracheae that run throughout the tissues of an insect, forming a complex network
main site of gas exchange
are completely permeable to gases
ventilation
the movement of fresh air into the lungs and stale air out of the lungs via inspiration and expiration
vital capacity
the largest volume of air that can be breathed in following the strongest possible exhalation
affinity
the tendency of one substance to bind with another substance
aorta
the artery that takes oxygenated blood away from the heart to the body
arteriole
a type of blood vessel that connects the arteries and capillaries
the walls contain large amounts of smooth muscle, some elastic fibres and some collagen
artery
type of blood vessel that carries blood away from the heart to the tissues, under high pressure
the walls contain collagen collagen, smooth muscle and elastic fibres
atrial fibrillation
an arrhythmia that involves the rapid contraction of the atria, preventing complete ventricular filling
atrial systole
the stage of the cardiac cycle in which the atria contract, pushing blood into the ventricles
the AV valves are pushed open fully and the atria are emptied of blood
atrioventricular node (AVN)
a group of cells located between the atria that slow down the wave of excitation and pass it between the ventricles, along the bundle of His
atrioventricular (AV) valves
found between the atria and ventricles
prevent the back flow of blood from the ventricles into the atria
two types of AV valves
bicuspid
tricuspid
bicuspid valves
the atrioventricular valves found between the left atrium and left ventricle
blood
the transport medium in the mammalian circulatory system
consists of plasma, red blood cells, white blood cells and platelets
bohr effect
the loss of affinity of haemoglobin for oxygen as the partial pressure of carbon dioxide increases
bradycardia
a slow resting heart rate below 60 bpm
bundle of His
a collection of purkyne fibres which run from the AVN down to the apex of the ventricles
capillaries
microscopic blood vessels
form a large network through the body tissues
connect the arterioles to the venules
site of exchange of substances between the blood and the tissues
carbonic anhydrase
an enzyme that catalyses the reversible reaction between water and CO2 to produce carbonic acid
cardiac cycle
describes the sequence of events involved in one complete contraction and relaxation of the heart
consists of 3 stages
stages of cardiac cycle
- atrial systole
- ventricular systole
- diastole
cardiac output
the volume of blood pumped by the heart through the circulatory system in 1 minute
cardiac output equation
heart rate x stroke volume
chloride shift
the process by which chloride ions move into the erythrocytes in exchange for hydrogen carbonate ions (which diffuse out of the RBC)
this maintains the electrochemical equilibrium of the cell
circulatory system
the transport system in animals
closed circulatory system
the blood pumped by the heart is contained within blood vessels
the blood doesn’t come into direct contact with the cells
found in animals (like vertebrates)
diastole
the stage of the cardiac cycle in which the heart muscle relaxes
the atria and ventricles fill with blood
double circulatory system
the blood flows through the heart twice in 2 circuits
blood is pumped from the heart to the lungs and then back to the heart
then pumped around the body and returns to the heart again
found in mammals (like humans)
ectopic heartbeat
additional heartbeats outside of the normal heart rhythm
electrocardiogram (ECG)
technique used to indirectly measure the spread of electrical activity through the heart
by measuring tiny changes in the skin’s electrical conductivity
this produces a trace which is used to detect abnormalities in the heart rhythm
haemoglobin
red pigment found in erythrocytes
binds reversibly with 4 ocygen molecules to form oxyhaemoglobin
globular protein that consists of 4 polypeptide chains, each with a prosthetic haem group
haemoglobinic acid
the product formed when haemoglobin accepts free hydrogen ions
enables haemoglobin to act as a buffer, reducing changes in blood pH
heart rate
the number of times the heart beats in one minute
hydrostatic pressure
the pressure exerted on the sides of a vessel by a fluid
inferior vena cava
the vein that returns deoxygenated blood to the heart from the lower body
lymph
modified tissue fluid that drains into the lymphatic system
carries less oxygen and fewer nutrients than tissue fluid, also contains fatty acids
myogenic
describes cardiac muscle tissue that initiates its own contraction, without outside stimulation from nervous impulses
oncotic pressure
the movement of water into the blood by osmosis due to the tendency of plasma proteins to lower the water potential of the blood
open circulatory system
the transport medium pumped by the heart is not contained within vessels but moves freely
the transport fluid comes into direct contact with the cells
found in invertebrates (like insects)
oxygen dissociation curve
a graph that describes the relationship between the partial pressure of oxygen and the percentage saturation of haemoglobin in the blood
plasma
the main component of the blood that carries RBC
is a yellow liquid that contains proteins, nutrients, mineral ions, hormones, dissolved gases and waste
pulmonary arteries
the arteries that carry deoxygenated blood away from the
heart to the lungs
pulmonary veins
the veins that carry oxygenated blood from the lungs up to the heart
purkyne tissue
specialised cardiac muscle fibres which make up the bundle of His
conduct the wave of excitation through the septum, from the AVN down to the apex of the ventricles
semilunar valves
pair of valves found between the ventricles and arteries
prevent back flow of blood from the arteries into the ventricles
septum
the wall of muscle which separates the left side of the heart from the right side
preventing oxygenated and deoxygenated blood from mixing
single circulatory system
the blood travels on circuit
blood flows through the heart and is pumped around the body before returning to the heart
found in fish
sinoatrial node (SAN)
group of cells in the wall of the right atrium that generate electrical activity, causing the atria to contract
often referred to as the heart’s pacemaker
stroke volume
volume of blood pumped by the left ventricle of the heart in a single contraction
superior vena cava
the vein that returns deoxygenated blood to the heart from the head and upper body
trachycardia
a rapid resting heart rate over 100 bpm
tissue fluid
the fluid that surrounds the cells of animals
has the same composition of plasma but does not contain RBC or plasma proteins
tricuspid valves
the atrioventricular valves found between the right atrium and right ventricle
vein
type of blood vessel that carries blood towards the heart under low pressure
have a wide lumen, a smooth inner lining and valves
the walls of the veins contain large amounts of collagen, smooth muscle and little elastic fibre
ventricular systole
the stage of the cardiac cycle in which the ventricles contract, pushing blood into the arteries
the semi-lunar valves are pushed open fully
venule
type of blood vessel that connects the capillaries and veins
the walls contain small amounts of collagen and smooth muscle
active loading
the process by which hydrogen ions are actively pumped out of companion cells using ATP, before diffusing down a conc gradient, back into the cells via co-transporter proteins, whilst carrying sucrose
adhesion (water movement)
the formation of hydrogen bonds between carbohydrates in the xylem vessel walls and water molecules
this contributed to the capillarity of water and transpiration pull
apoplast route
one of two pathways by which water and minerals move across the root
water moves through the intercellular spaces between cellulose molecules in the cell wall
casparian strip
a waterproof strip surrounding the endodermal cells of the root that blocks the apoplast pathway, forcing water through the symplast route
cohesion (water movement)
the formation of hydrogen bonds between water molecules
this contributes to the capillarity of water and transpiration pull
cohesion-tension theory
the model that explains the movement of water from the soil to the leaves, in a continuous stream
companion cells
the active cells of the phloem located adjacent to the sieve tube elements
they retain their nucleus and organelles, producing ATP for metabolic processes in both themselves and the sieve tube elements
dicotyledonous plants
plants that produce seeds that contain two cotyledons
they have two primary leaves
hydrophytes
plants that are adapted to live and reproduce in very wet habitats (like water lillies)
phloem
a living plant transport vessel responsible for the transfer of assimilates to all parts of the plant
the phloem consists of sieve tube elements and companion cells
plasmodesmata (phloem)
small pores between adjacent sieve tube elements and companion cells that allow communication and the exchange of materials
potometer
an apparatus used to measure water uptake from a cut shoot
root hair cells
specialised cells responsible for the uptake of water and minerals from the soil
they have long hair-like extensions (root hairs - adapted as exchange surfaces)
sieve plates
the perforates end walls of sieve tube elements that allow plant assimilates to flow between cells unimpeded
sieve tube elements
the main cells of the phloem
elongated cells laid end to end with sieve plates between
contain few organelles
sinks (plants)
the regions of a plant that remove assimilates (like roots, meristem + fruits)
sources (plants)
the regions of a plant that produce assimilates (like leaves, storage + organs)
symplast route
one of two pathways by which water and minerals move across the root
water enters the cytoplasm through the plasma membrane and moves between adjacent cells via plasmodesmata
water diffuses down its water potential gradient by osmosis
translocation
the movement of organic compounds in the phloem, from sources to sinks
transpiration
water loss form plant leaves and stems via diffusion and evaporation
affects the rate of transpiration
- light
- temperature
- humidity
- air movement
- soil-water availability
transpiration stream
the flow of water from the roots to the leaves in plants, where it is lost by evaporation to the environment
vascular bundle
the vascular system in herbaceous dicotyledonous plants
it consists of two transport vessels - the xylem and the phloem
vascular system
a network of transport vessels in animals and plants
xerophytes
plants that are adapted to live and reproduce in dry habitats where water availability is low (like cacti and marram grass)
xylem
a non-living plant transport vessel responsible for the transfer of water and minerals from the roots to the shoots and leaves
