PSL280 Final review
Focus of New material
o Composed of Nares / blow holes Nasal cavity Larynx(voicebox)
tracheapirmary bronchisecondary bronchibronchibronchiolsalveoli
o * cartilage of the repiratory is usually complete rings
o *process of breathing( opening air way) is voluntary, closing is passive
o Mysticete2 blow holes Odontocete one blow hole
o Cetacean and pinniped larynx
Goose beak is supported by thyroid cartilage ( cetaceans)
Separates breathing and feeding
Short trachea which consists of cartilage rings
o Beluga/ sperm(5-7) dugong(4) manatee (8-12)
Pinnipeds 2 arytenoids or throat cartilages that help close off the
Pinnipeds have same sized lungs but the right has 4 and left has 3
Cetaceans have a larger , longer and heavier right lung heart
o Cetacean have more cartilaginous support
o Small residual lung volume massive tidal volume
Sea otter: RL( 4 lobes) LL(2lobes) large lung capacity not for
diving but buoyancy.
Polar bears: have no lung adaptation
Sirenia: extremely long lungs almost as far as the kidneys and aid
in buoyancy control
o Diaphragm is under lungs and runs lengthwise
Cetaceans: primary bronchus runs entire length, few secondary.
o Small tubes run from bronchioles respiratory vesicles along
the bronchioles instead of at the end of them
Sirenia: very muscular bronchioles used to compress air and
o Phocid: bronchiol is completely reinforced with muscle and
some cartilage, muscle extends from bronchiole to alveoli
o Otariid: bronchiole is mostly supported by cartilage,
cartilage extends to mouth of alveolar sacs. Muscle doesn’t
extend full bronchiole length o Odobenidae
Bronchiol is supported by all muscle with little
cartilage, muscle extends with some cartilage
3 origins, directly from cartilaginous airways, off of
muscle and at ending.
o Osmoregulation: balance between water intake and the excretion of minerals to
maintain certain levels.
o From the Kidney, the ureter drains urine from the hilus and collects it into the
o Excretion: filtration + excretion – resorption.
o Cortical medullary axis: counter current concentrator
o Reniculated kidneys
Rennicles are composed of the cortext and its own medulla so there are
many miniature kidneys with in one multireniculated kidney.
The number of renicles correlates with the selenity of the diet. * The
number of renicles in a dolphin would be more than in a manatee due to
the fresh water.
o 3 basic sources that animals can obtain water for osmoregulation
Drink fresh water directly
Water from food
Water produced by metabolism
1g of fat 1.07 g of H2O
o Water loss prevention
Lower water content of air exhaled,
Concentrate urine more and feces
Reduce sweating or sweat glands
The drinking of seawater due to high protein diet makes it possible to
excrete Urea from the body. Sea otters area good example.
Sea otter : 62ml/kg
Fur seal 1.8ml/gh
Harbor seal 4.8ml/kg
Common dolphins 12-13 ml/kg.
o Which groups tend to need the least and the most parental care?
Cetaceans and sirenians: need little care or protection
Pinnipeds/Polar bears and Sea otters: need lots of care so mom loses body
o What groups give birth in water and on land? Polar bears and Pinnipeds : on land
Cetaceans, sirenians and sea otters: in water
o Where do certain groups breed, water or land?
Cetaceans , sirenians , Sea otters, and pinnipeds( walrus) breed in water
Polar bears, some pinnipeds ( elephant seals) breed on land
Some pinnipeds( gray seals) breed in both water and land.
o What are the actions of the parents while raising young?
Cetaceans, sirenians, sea otters, and walrus : still forage while feeding
Polar bears and elephant seals: cause the females to fast while raising
o Go and memorize gestation rates and reproductive cycle intervals.
o Reproductive anatomy
Females all have : ovaires, oviducts, uterus, cervix, vagina, clitoris and
Uterus differences amongst marine mammals
Simplex; humans; 1 uterine body/no horns; 1 cerix
Duplex : walrus : 2 horns : 2 cervix
Bipartite: phocids: 2 horns septated: 1 cervix
Bicornuate: cetaceans/ sirenians/ seaotters/ polar bears: 2 horns no
septum with single body; 1 cervix
Cervix: muscular sphincter that separates the uterus from the vagina
Manatees: west indian has a rounded cervix but Dugongs have a
shield that starts in the uterus and surrounds the cervix
Cetaceans have a cervix that is long and tubular that opens into the
vagina lots of variation among species
o Long in the harbor porpoises but short in narwhals
Phocids: lying under blubber in CT sheath
Otarids: lying under blubber covering ventral body surface
Cetaceans: have nipple slits with the mammary gland lying on both
sides of the ventromedial line between the umbilicus to above the
anus. cutaneous trunki is what contracts these mammary glands.
Cetaceans: 2 ventromedially
Sirenians: under pectoral flippers