Week 5 Flashcards
among multicellular organisms, simplest NS in
cnidarians
cephalisation
concentration of NS components at one end of the body, defined as the ‘front’
worms
evolved independently multiple times in different animal groups
hydrostatic skeleton
500 MYA in cnidarians
nearly all multicellular animals and many vascular plants
fluid contained within a body cavity serves as supportive component
muscles act on fluid filled cavity
invertebral disks
between vertebrae of backbone
allow it to twist and bend
Exoskeleton
650 MYA in sponges hard external support muscles attach from inside limit growth and prone to breaking, cannot be repaired arthropods
molting:
arthropods shed their cuticle at intervals so they can expand and grow before forming a new exoskeleton
Endoskeletons
30-500 MYA in vertebrates internal to soft tissue can grow and repair protects key organs divided into axial and appendicular regions
axial skeleton
skull and jaw of head
vertebrae of spinal column
ribs
appendicular skeleton
bones of limbs
operculum
protective flap in fills that expands to draw water over gills
tidal ventilation of internal lungs
thoracic cavity expanded to draw air inside lungs
expansion of lungs causes air pressure to become lower than outside
resulting negative pressure draws air into lungs
Intercostal muscles assist diaphragm by elevating ribs on inhalation
ventilation rate
breathing frequency x tidal volume
carotid bodies
sense O2 and proton concentrations of the blood going to the brain
Aortic bodies
monitor levels of O2 and proton in blood moving to the body
Breathing sensors
chemoreceptors in brainstem and sensory structures called carotid and aortic bodies
blood resistance determined by
fluid viscosity
vessel length
mainly vessel radius
arteries
blood away from heart to tissues
more pressure
co2, increase acts as a signal to the smooth muscle to relax, allowing arterioles to increase in diameter
So blood flow increases to the capillaries to match O2
Artery walls expand momentarily from heartbeat pressure because of collagen and elastin
veins
return blood from tissues to heart
low pressure
Blood returns to heart through venae cavae
fish CS
two chambered hearts
single circulatory system
atrium and ventricle
Deoxygenated blood from fish tissues enters atrium, which fills and contract to move blood into a thicker walled ventricle
Oxygenated blood collected from the gills travels to the tissues through aorta
The small gill capillaries impose a large resistance to flow. As a result, much of the blood pressure is lost in moving blood through the gills. This loss of pressure limits the flow of oxygenated blood to body tissues.
amphibians CS
three chambered hearts
partially divided circulations
two atria and single ventricle
Single ventricle so oxygenated blood returning to the heart from the gills or lungs mixes with deoxygenated blood returning from the animals body before being pumped from the ventricle
mammals and birds CS
four chambered hearts
fully divided pulmonary and systemic circulations
diastole
relaxation of ventricle
atria contract, filling the ventricles with blood
systole
contraction of ventricles
ventricles contract, pumping blood out of the heart
cardiac muscle cells
found in sinoatrial and atrioventricular nodes
Cardiac output
volume of blood pumped by the heart over a given interval of time
HR x stroke volume
stroke volume
volume of blood pumped during each beat
Starling’s law
relationship between the volume of blood filling the heart and stroke volume
a greater volume of blood returned to the heart increases stretching of the muscles
leads to more forceful ejection of blood and a greater stroke volume
Ganglia
groups of nerve cell bodies that process sensory information received from a local resulting in a signal to motor neurons that control some physiological function of the animal
sponges NS
Have none
cephalisation advantages
forward locomotion, nearness of sensory organs to central ganglia/brain makes it possible to process this information quickly; easier to detect and capture prey
hydrostatic skeleton length and diameter
Circular muscle reduce diameter of body cavity and longitudinal muscles reduce its length
In addition to tendon, three main extracellular tissues are produced in the formation of the vertebrate skeleton:
bone
tooth enamel
cartilage
osteoblasts
synthesise and secrete calcium phosphate as hydroxyapatite mineral crystals in close association with the protein collagen
articular cartilage
located at the joint surfaces of a bone forms a cushion between bones meeting at a joint
gills
Large aquatic animals
Some sessile invertebrates have external gills but they are easily damaged and eaten by predators
Actively pump water through mouth over gills to ventilate
concurrent flow
when hot and cold water move in same direction, both become warm
countercurrent flow
when hot water and cold water move in opposite directions, hot becomes cold and cold becomes hot
trachea- insects
They rely on a two step process of ventilation and diffusion to supply cells with oxygen and eliminate CO2 unlike in terrestrial vertebrates
Enters through spiracle openings along abdomen; ventilated through trachea; direct to cells; co2 diffuses out our cells and eliminated through trachea
characteristics of air allowing tidal ventilation
low density and viscosity
tidal volume of lungs
at rest, inhale and exhale about 0.5 L of air every cycle
gas exchange in birds
In birds, air is taken in through mouth, then nasal passages through larynx, then trachea, primary bronchi
To exhale, posterior sacs expands and air taken to mouth
Air capillaries direct the air so that it moves crosscurrent to the blood flow- so more oxygen extracted from air than in mammals
After gaining co2, air from lungs enters anterior air sacs and posterior air sac again inflated by fresh air
reptile CS
three chambered heart
two atria and single ventricle
their single ventricle has internal ridges to improve the separation of deoxygenated and oxygenated blood
so reptiles more able to deliver oxygen to tissues than amphibians
Amphibian CS process
deoxygenated blood from the tissues enters the right atrium from a major vein and is pumped into the single common ventricle
oxygenated blood from the lungs enters the left atrium and is pumped into the ventricle
mixed oxygenated and deoxygenated blood is pumped out of the common ventricle into separate arteries leading to the lungs and tissues
mammals and birds CS process
deoxygenated blood enters the right atrium from the inferior and superior venae cavae
deoxygenated blood passes through the right AV valve into right ventricle
deoxygenated blood is pumped into the pulmonary arteries through the pulmonary valve
to the lungs
MEANWHILE
Oxygenated blood returns from the lungs through the pulmonary veins to the left atrium
Oxygenated blood enters the left ventricle through the left AV valve
Oxygenated blood is pumped by the left ventricle through the aortic valve into systemic circulation
Walls of the right ventricle- birds and mammals
thinner than left with weaker contractions
blood at lower pressure
moves slower so more time for gases to diffuse in and out of lungs
cardiac cycle
contraction of the two atria followed by contraction of the two ventricles; divided into 2 phases; Diastole- relaxation of ventricles; systole- contraction of ventricles
atrial muscle cells
must contract in synchrony during diastole to fill ventricles
ventricular muscle cells
must contract in synchrony during systole to eject blood from the heart
pulmonary veins carry
oxygenated blood from the lungs to the left atrium
path of a drop of blood leaving the human heart
heart → arteries → arterioles → capillaries → venules → veins → heart
The heartbeat originates in the
sinoatrial node located at the junction of the vena cava and the right atrium.
Which of the following blood vessels play an important role in controlling blood flow to different regions of the body through the contraction and relaxation of smooth muscles in their walls?
arterioles
At any given point along the length of the gill lamella, how does the pO2 of the blood flowing through the blood vessels in the lamella compare to the pO2of the water flowing over the gill lamella?
The pO2 of the blood is lower than the pO2 of the water.
At the venous end of a capillary, the blood pressure is _____ the osmotic pressure and fluid _____ the blood vessel.
lower than; moves into
Atrioventricular valves separate
the left atrium from the left ventricle and the right atrium from the right ventricle.
