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