Download Animal Structure and Function

Animal Structure and
Function
Thermoregulation
► Ectotherms
 Obtain body heat from the environment.
 Poikilotherms
►Invertebrates,
►“cold
amphibians, reptiles and fish.
blooded”
► Endotherms
 Generate their own body heat.
 Homeotherms
►Mammals
►Warmblooded
Temperature Regulation
► Cooling
evaporation
 Sweating
 Panting
► Warming
by metabolism
 Shivering
► Adjusting
surface area
 Changing the volume of blood flow
 Countercurrent Exchange
The Respiratory System
► Direct
contact with the environment
 Cells have large surface areas with which they can
have exchange with the environment.
► Gills
 Evaginated structures that create large surface areas.
► Tracheae
 Chitin lined tubes that permeate the body.
 Oxygen enters the tracheae through opening called
spiracles.
► Lungs
 Invaginated structures which allow gas exchange
Human Respiration
► Nose,
pharynx, larynx
► Trachea
► Bronchi, bronchioles
► Alveolus
► Diffusion between alveolar chambers and blood.
► Bulk flow of O2
► Diffusion between blood and cells
► Bulk flow of CO2
Circulatory System
► Open
Circulatory Systems
 Blood is pumped into an internal cavity-hemocoel
 The tissues and organs are bathed in hemolymph.
 Hemolymph returns to the heart through holes called
ostia.
► Mollusks,
► Closed
insects
Circulatory Systems
 Blood is confined to vessels.
► Annelida
Octopuses, Squid, Vertebrate
Human Circulatory System
► Basics:
 Arteries  arterioles  Capillaries Gas and
waste exchange  Venules  Veins  Heart
Pumping Blood Through the Heart
►
Right Atrium
 Deoxygenated blood enters via the superior vena cava and inferior
vena cava
►
Right Ventricle
 Blood moves through the tricuspid valve (right atrioventricular valve
or AV valve) to the right ventricle.
 Right ventricle pumps the blood to the pulmonary artery through
the pulmonary semilunar valve to the lungs.
►
Left Atrium
 Oxygenated blood returns to the left Atrium through the pulmonary
vein.
►
Left Ventricle
 Blood moves through the bicuspid (mitral or left AV valve) to the
left ventricle.
 The blood is then pumped from the heart via the aorta through the
aortic semilunar valve and to the body.
The Cardiac Cycle
► The
rhythmic contraction and relaxation of heart
muscles.
► Regulated by auto rhythmic cells which are selfexcitable.
 SA node, pacemaker
► Upper
wall of the right atrium
► Initiates the cycle by contracting both atria
 AV node
► Lower
half of the right atrium
► Receives a delayed impulse from the SA node then contracts
the ventricles.
 Systole Phase
► Blood
is forced through the pulmonary arteries and aorta and
the AV valves are forced to close.
Blood
► RBC,
erythrocytes
 Transport oxygen
► WBC,
leukocytes
 Disease fighting cells
► Platelets
 Cell fragements
 Blood clotting
► Plasma
 Liquid
The Excretory System
► The
excretory systems help maintain
homeostasis in organisms by regulating
water balance.
Osmoregulation
► The
absorption and excretion of water and
dissolved substances so that proper water
balance is maintained between the
organism and its surroundings.
 Marine fish
►Hypoosmotic
►Drink
lots, pee little
 Fresh water fish
►Hyperosmostic
►Drink
little, pee lots
Excretory Mechanisms
► Contractile
► Flame
Vacuoles
Cells
► Nephridia
► Malpighian tubules
► Kidney
Contractile Vacuole
► Vacuole
accumulates water and then
merges with the plasma membrane to
release the water
Flame Cells
► An
internal cilia that moves wastes out of
the cell.
Nephridia
► Fluids
are concentrated as they pass
through a collecting tubule.
► Blood capillaries that surround the tubule
reabsorb necessary materials.
► The concentrated waste materials are
excreted through an excretory pore.
► Early tubular excretory system
Malpighian Tubules
► Tubes
attached to the midsection collect
body fluids from the hemolymph.
► Wastes are deposited into the midgut and
out the anus
Kidney
► Nephrons
filter blood.
► Waste is collect and excreted through the
ureters to the bladder.
► Urine is excreted through the urethra.
Nephron Parts
► Bowman’s
capsule
► Convoluted Tubule
► Collecting Tubule
Bowman’s Capsule
► Bulb-shaped
body.
► Renal artery (afferent arteriole) enters into
the Bowman’s capsule to form a dense ball
of capillaries
 Glomerulus
► Then
exits the capsule (efferent arteriole)
Convoluted Tubule
► Begins
with the proximal convoluted tubule
at Bowman’s capsule.
► Ends with the distal convoluted tubule
where it joins with the collecting duct.
► Middle: Loop of Henle
 Descending and ascending limb
Collecting Duct
► Descends
to the center of the kidney.
► Shared by multiple nephrons
► Empties into the renal pelvis
 Drains into the ureter
How does the Nephron Work
► Filtration
 Blood enters the glomerulus
 Filtrate that enters flows into the convoluted tube.
► Secretion
 Filtrate passes through the proximal tubule and distal
tubule.
 Interstitial fluids join the filtrate from the capillary
network.
► Reabsorption
 Filtrate moves down the loop of Henle water moves out.
 Filtrate moves up the loop of Henle and salts are
removed.
 Filtrate descends through the collecting duct toward the
renal pelvis as concentrated urine.
Hormones
► Influence
osmoregulation by regulating salts
concentration
 Antidiuretic hormone (ADH)
►Increases
reabsorption of water by the body.
►Increasing the permeability of the collecting duct to
water.
 Aldosterone
►Increases
the reabsorption of water and sodium.
►Increasing the permeability of the distal convoluted
tubule and collecting duct to sodium.
Nitrogen Waste
► Toxic
ammonia is the result of amino acids
and nucleic acids.
 Mechanisms to rid the body
►Aquatic
animals excrete NH3 directly into the
surrounding water.
►Mammals convert NH3 to urea in the liver.
►Birds, insects and reptiles convert urea to uric acid.
 Concentrated precipitate
The Human
Digestive Tract
a.k.a. alimentary canal
mouth
esophagus
stomach
Small intestine
Large intestine
rectum
•Ingestion occurs here
•Mechanical digestion via teeth
and tongue; formation of bolus
•Chemical digestion of starch
begins by salivary amylase.
mouth
esophagus
stomach
Small intestine
Large intestine
rectum
•Epiglottis blocks the trachea so that
solid food and liquids only enter.
•Carries food from mouth to
stomach
•bolus moves along via peristalsis
(tennis ball in a sock)
esophagus
stomach
Small intestine
Large intestine
rectum
•Mechanical
•Food is temporarily
digestion stored
thanks
to
here
muscular
(now called
walls of
chyme)
this organ
•Chemical digestion of protein
begins by pepsin. Secreted as
pepsinogen and activated by
HCl mucus lining protects
•Special
•pyloric sphincter
walls
from acidity
controls
movement of
chyme into small
intestine
stomach
Small intestine
Large intestine
rectum
•Remainder
of
Smalldigestion
Intestine:
•Duodenum:
•Liver: Mechanical
proteases
digest of
•Pancreas:
produces
enzymes
monosachharides,
amino
acids,
proteins,
lipid thanks
maltase
to bile
and
(made
lactase
in
proteases,
lipase,
and
and
nucleotides
are absorbed
digest
liver/stored
disaccharides
in gall
bladder)
and
pancreatic
amylase
into
bloodfats
vessels
inand
villianand
phosphateases
emulsify
digest
alkaline
solution.
microvilli
nucleotides
Small intestine
(small diameter, long length)
Large intestine
rectum
•Appendix is found at the
junction of the small and large
intestine (called a cecum in
herbivors and larger)
•Contains helpful bacteria which
make some vitamins we need
•Absorbs water and vitamins
Large intestine
(large diameter, short length)
rectum
•stores feces until egestion
rectum
•egestion occurs here
Hormones
► Gastrin
 Produced in the stomach
 Enters the blood stream to stimulate the cells of the
liver to produce gastric juices.
► Secretin
 Produced by the duodenum when food enters.
 Stimulates production of bicarbonate which neutralizes
the acid.
► Cholecystokinin
 Produced by the small intestine.
 Stimulates the gallbladder to release bile and the
pancreas to release enzymes
Nervous System
► Basic
structural Unit: Neuron
► 3 Parts:
 Cell Body
 Dendrite
 Axon
►Dendrite
Axon
 Cell Body  Axon  Branches of the
3 Neuron Groups
► Sensory
Neurons (afferent neurons)
 Receive the initial stimulus
► Motor
Neurons (efferent neurons)
 Stimulate target cells (effectors) that produce some
type of response.
► Association
Neurons (interneurons neurons)
 Located in the spinal chord or brain.
 Receive impulses from sensory neurons or send
impulses to motor neurons.
 Intergrators: Evaluate impulses for appropriate
responses.
How does it work?
► Overview
 Is the result of chemical changes across the membrane
of the neuron.
 Unstimulated neuron is polorized
► The
inside of the cell is negative with respect to the outside.
 Polarization is established by maintaining an excess of
sodium on the outside and an excess of potassium on
the inside.
 Other negatively charged ions such as protiens and
nucleic acids reside inside the cell resulting in the overall
negative charge on the inside of the cell membrane.
Events of Nerve Impulse
Transmission
► Resting
potential
► Action potential
► Repolarization
► Hyperpolarization
► Refractory period
Resting potential
► Unstimulated
polized state.
Action potential
► Stimulus
► Gated
ion channels in the membrane
suddenly open and permit the sodium on
the outside to rush into the cell.
► The mebrane becomes depolarized.
 If the stimulus is strong enough (above the
threshold level) more sodium gates open.
 The action potential continues down the