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Circulation, Gas exchange and Osmoregulation, excretion (Chapter 44:…
Circulation, Gas exchange and Osmoregulation, excretion
Chapter 42: Circulation and Gas exchange
Circulatory system link exchange surfaces will cells throughout the body, Coordinated cycles of heart contraction.
Gastrovascular cavity
Mediates exchange between the environment and cells that can be reached by Diffusion
Arthropods and most molluscs have an
open circulatory system
hemolymph
bathes organs directly
Vertebrates have a
closed circulatory system
blood
circulates in a closed network of pumps and vessels
consists of blood, blood vessels, and a two-chambered heart
Closed Circulatory System
blood pumped by a heart ventricle passes to arteries then to the capillaries.
Veins return blood from capillaries to an atrium, which passes blood to a ventricle.
Fish, rays, and shark have a single in their circulation.
Air-breathing vertebrates have two pumps combined in a single heart
Cardiac cycle
systole
A complete sequence of the heart's pumping and filling, consists of a period of contraction.
heart function can be assessed by measuring the
pulse
and
cardiac output
heartbeat originates with impulses at the
Sinoatrial node (SA)
Can trigger atrial contraction, are delayed at the
Atrioventricular node (AV)
Blood components and Gas Exchange occurs across specialized respiratory surfaces
Plasma
proteins influence blood pH, osmotic pressure, and viscosity
Platelets function in blood clotting, a cascade of reactions that converts plasma fibrinogen to fibrin.
Erythrocytes
(red blood cells) transport O2-five types of
leukocytes
(white blood cells)
Function in defense against microorganisms and foreign substances
Sickle-cell disease
form of hemoglobin that disrupts erythrocyte shape and function
lead to blockage of small blood vessels and a decrease in the oxygen-carrying capacity of blood.
cardiovascular disease
inflammation of the arterial lining enhances deposition of lipids and cells, resulting in the potential for life-threatening damage to heart or brain.
Gas Exchange
Gas undergoes net diffusion from where its
partial pressure
higher to where it is lower
Air is more conductive to gas exchange than water
Effectiveness of gas exchange
in some gills(fishes) is increased by ventilation and countercurrent exchange between blood and water
in insects it relies on a
tracheal system
A branched work of tubes that brings O2 directly into cells.
Spiders, land snails, more terrestrial vertebrates have internal lungs
mammals inhale through the nostrils passes through the pharynx and into the
trachea, bronchi, bronchioles, and alveoli
Amphibian ventilates its lungs by
positive pressure breathing
Forces air down the trechea
Mammals ventilate their lungs by
negative pressure breathing
Pulls air into the lungs when the rib muscles and diaphragm contract.
Chapter 44: Osmoregulation and excretion
Osmoregulation balances the uptake and loss of water and solutes
Osmoconformers
isosmotic with their marine environment and do not regulate their osmolarity.
Control water uptake and loss in a hypoosmotic or hyperosmotic environment
Fresh water fish:
lives in water les concentrated than body fluids; fish tends to gain water and lose salt
Marine bony fish:
lives in water more concentrated than body fluids; fish tends to lose water and gain salt
Terrestrial Vertebrate:
terrestrial environment; tends to lose body water to air
Ammonia
Aquatic animals excrete it.
mammals and adult amphibians convert it to the less toxic
urea.
excreted with a minimal loss of water
Protein and nucleic acid metabolism generates it.
insects and reptiles convert ammonia to
uric acid
mostly insoluble waste excrete in a paste-like urine
Excretory system
carry out filtration, reabsorption, secretion, and excretion
invertebrate include the protonephridia of flatworms
metanephridia of earthworms
malpighian tubules of insects
Kidneys function in both excretion and osmoregulation in vertebrates
Excretory tubules
consist of nephrons and collecting ducts
blood vessels pack the mammalian kidney
blood pressure forces fluids from blood in the glomerulus into the lumen of bowman's capsule
then reabsorption and secretion, filtrate flows into a collecting duct
Ureter conveys urine from the renal pelvis to the urinary bladder
Nephron
selective secretion and reabsorption in the proximal tubule alter filtrate volume and composition
In mammals, a countercurrent multiplier system involving the loop of Henle.
Maintains the gradient of salt concentration in the kidney interior
Henle extend deep into the renal medulla.
ADH increases the permeability to water of the collecting ducts.
By increasing the numbers of epithelial aquaporin channels.
When blood pressure or blood volume in the afferent arteriole drops, the juxtaglomerular apparatus releases renin
Renin-angiotensin-aldosterone system has a function that overlap with those of ADH and are opposed by atrial natriuretic peptide.