Mammology Lab Practical

ricochetal

A style of saltatorial locomotion that involves quick changes in the direction of travel

How do the orbits, rostra, and auditory bullae differ between the canid (a carnivore) and the rodent? Do these differences provide insight into the general food habits of these mammals?

The orbits, rostrum, and auditory bullae are bigger in the canids showing that canids probably rely on their eyesight (orbits) for hunting, rostra - lengthened auditory passage for increased smell, and larger bulla for better hearing. These seem like hunting improvements which makes sense because rodents don't hunt like canids.

Monocytes

They are the largest of the formed elements. Their cytoplasm tends to be abundant and relatively clear. They function in differentiating into macrophages, which are large phagocytic cells, and digest pathogens, dead neutrophils, and the debris of dead cells. Like lymphocytes, they also p resent antigens to activate other immune cells.

Eosinophils

They function in the destruction of allergens and inflammatory chemicals, and release enzymes that disable parasites

Neutrophils:

They play roles in the destruction of bacteria and the release of chemicals that kill or inhibit the growth of bacteria

Basophils

They secrete histamine which increases tissue blood flow via dilating the blood vessels, and also secrete heparin which is an anticoagulant that promotes mobility of other WBCs by preventing clotting

The zygomatic arch and sagittal crest are

origin of temporalis muscle (muscle of mastication (chewing muscles)) - picture: zygomatic arch. sagittal crest: the long arch on back of head you know about

what kind of horns do giraffes have

ossicones

inferior colliculi

primary auditory (sound) center

superior colliculi

primary integrating centers for eye movements

pineal body

produces melatonin, which regulates circadian rhythms

tapetum lucidum

reflects light to improve night vision

pons

respiratory centers (inhalation and exhalation)

Pulmonary Trunk goes to

right Atrium?

cursorial

running

soft palate

separates the nasopharynx from the oropharynx when you swallow it moves up so food doesn't enter up into nasals

Platelets

small fragments of bone marrow cells (megakaryocytes). They are involved in blood clotting by forming a platelet plug and secreting chemicals that accelerate the clotting cascade

The adult mammalian testis performs two important functions:

spermatogenesis and male sex hormone production

Cerebrum

the largest part, consisting of two cerebral hemispheres. its functions include: control of movement, sensory processing, olfaction, communication, learning and memory

mammalian foramen magnum: How does this compare to quadrupeds?

the mammalian vertebral column allows far greater freedom of head movement and powerful dorsoventral, rather than lateral, flexion of the spine.

auditory ossicles (malleus, incus, stapes)

transmit energy from the tympanic membrane to the oval window

tympanic membrane

transmits energy to the auditory ossicles

unguligrade

walk on the tip of the toe

digitigrade

walking on toes

corpus callosum

white matter that permits communication between the cerebral hemispheres

nasal conchae

(scroll-shaped bony elements covered by mucous membrane. form the upper chambers of the nasal cavities) increase surface area of these cavities, thus providing for rapid warming and humidification of air as it passes to the lungs (less smell = reduced nasal conchae))

Identify the bones of the rabbit skeleton. What are skeletal modifications for saltatory locomotion?

- Elongated rear limbs (metatarsals) for launch

Identify the bones of the bat skeleton. What are skeletal modifications for flight?

- Pectoral ring: T shaped manubrium that articulates with the first two pairs of ribs and the last two cervical vertebrae fused with the first two thoracic vertebrae - Tendon locking mechanism: rear legs - can hang upside down without consciously working the muscles that allow them to do so

Identify the bones of the dolphin forelimb. How is the forelimb different than other homologous mammal forelimbs?

- Steering and locomotion primarily

What are the functions of metatherian epipubic bones?

- That's typically where the pouch is

Identify the bones of the manatee forelimb. How does it differ from the dolphin?

- They can manipulate their hands like humans, hug each other etc. - It looks v different - more like a hand and no like a flipper

graviportal limb

-type of terestrial locomotion -large heavy species -legs directly under for support describe a graviportals limbs -5 digits arranged in a circle around foot -upper limbs longer than lower -knee and ankle joints nearly vertical -pad of elastic tissue fill gap behind toes to spread weight

Identify the structures that make up the sternum

...

Formed elements are:

1. Erythrocytes, also known as red blood cells (RBCs) 2.Leukocytes, also known as white blood cells (WBCs) 3. Thrombocytes, also known as platelets

Note the picture of the kangaroo rat skull. In lecture (Chapter 13), we discussed two specific reasons for the enlarged auditory bullae

1. Helps with hearing at night 2. Balance for erratic hopping (they don't hop straight as they run from predators)

Red blood cells have two main functions:

1. To pick up oxygen from the lungs and deliver it to tissues elsewhere 2. To pick up carbon dioxide from other tissues and unload it in the lungs

Platypus skeleton. How do monotreme skeletons resemble those of reptiles?

1. additional bones in pectoral (thoracic) girdle [ filiform sperm (it's stringy) ] 2. reptilian stance

The mammalian skull is a complex structure that serves two primary functions

1. protects brain 2. muscle attachment

What is the maximum number of incisors in the placental mammal skulls? *How do marsupials differ?*

4- gibbon 10- opossum , 6 In kangaroo, 8 tasmanian devil *Metatherians - top and bottom usually different, Placentals - most is 6*

Write the combined dental formulae Aardvark: Two toed sloth: Harbor Seal:

Aardvark: 5/4? homodont Two toed sloth: I 4/3 C 2/2 Harbor Seal: I 3/2 C1/1 PM+M 5/5

Which mammals are edentate, lacking teeth entirely? How does diet relate to dentition?

Anteater and platypus - edentate Anteaters eat ants, platypuses eat small aquatic arthropods etc.

What is the function of the occipital condyles?

Articulate with the first cervical vertebrae (condyle refers to articulation)

How is the eye socket placement in beavers an example of form and function?

Beavers have eyes set backwards in skull a bit - this could be for their ability to swim forward etc.

Consider the photograph of the horse showing the muscle mass in the limbs. Where is the bulk of the muscle? How does the anatomy of the humerus relate to this?

Behind the scapula and humerus. Running! Our thighs are bigger than calves etc.

Equine limbs Which bones in the distal limbs are elongated. How does this relate to locomotion?

Elongated and fused metatarsals in front leg - proximal phalanx is also elongated Stride length

brachiating

locomotion accomplished by swinging by the arms from one hold to another

elk teeth

looks selenodont diet: grasses, tree leaves, twigs, and shrubs

function of walrus tusks

Fighting/ breeding status

Do you see evidence of reduction in bone numbers or fusion of bones?

Fusion / reduction of bones that makes hooves. Elongated and fused metatarsals in front leg - proximal phalanx is also elongated

meatuses

narrow passageways within the nasal conchae

Nutria/capybara teeth

Hypselodont teeth in nutria and capybara - constantly worn down

Dental Formulae four letters

I: incisor C: canine PM: premolar M: molar

What do you notice about the arrangement of incisors in the cow, deer, and sheep?

Incisor teeth are found in the rostral (front) portion of the mouth, but they are absent from the upper jaw

Manatee skull. How does this mammal's feeding habits relate to tooth replacement? Which types of teeth are not present?

It eats plants on the ground so it gets sand and wears it down so it has constant tooth replacement. I only saw cheek teeth/incisors no canines etc.

Why do the ventricles vary in thickness?

Left is thicker because it pumps the blood and it's a muscle variations in the amount of myocardium present

Lymphocytes

Lymphocytes function in destroying cancer cells, cells infected by viruses, and foreign invading cells. In addition, they present antigens to activate other cells of the immune system. They also coordinate the actions of other immune cells, secrete antibodies and serve in immune memory.

eye position on predators vs prey

Most all predators have eyes located in a forward position on the skull. Herbivores are strictly prey and most have orbits located on the side of the skull

olfactory bulbs

nerves from the nasal mucosa enter the cranium and synapse with these bulbs (sense of smell).

Tasmanian Devil, Tasmanian Wolf, Numbat order (meh)

Order: Dasyuromorphia

Opossum Identify the order. (meh) What incisor characteristic (numbers) do metatherians share? What are the incisor numbers for this skull?

Order: Didelphimorphia Opossum: I 5/4 C1/1 PM+M 7/7

Platypus, Short Nosed Echidna order describe teeth What covers the bony aspect of the rostrum? What receptor types are located there?

Order: Monotremata nah rostrum has leathery covering > electroreceptors, mechanoreceptors

Short Nosed Bandicoot order (meh) Use skull or tooth characteristics to determine the feeding type

Order: Peramelemorphia Omnivores - lil flatness to cheek teeth - not quite as sharp

Compare the cheek teeth of marine mammals (sea otter, sea lion, dolphin). What features give you clues about which of these mammals are fish eaters and which eat primarily molluscs and echinoderms?

Sea otter: flatter crushing teeth (I know eats molluscs etc). Sea lion: all teeth look sharper like canines Dolphin: has sharp homodont (?) all same looking sheering teeth

True horns - ? Pronghorns - ? Antlers - ? Ossicones - ? Rhinoceros "horns" - ?

True horns - cow Pronghorns - black... Antlers - muntjak Ossicones - giraffe Rhinoceros "horns" - keratin

plantigrade

Walking on the soles of the feet, like a human or a bear.

Can you give the complete dental formulae of these carnivores? Identify the carnassial teeth. wolf + coyote

Wolf: I 3/3 C 1/1 P4/4 M 2/3 Coyote: I 3/3 C 1/1 P 4/4 M 2/3 :)

ear canals of cetaceans

not thought to be functional do not attach to the tympanic membrane (ear drum) (?)

What is the function of the foramen magnum?

openings in bone - passage of vessels and nerve

Trachea: Note the C-shaped cartilages that support the trachea. What is the significance of the open end of the "C" being posterior?

allow the trachea to collapse slightly at the opening so that food can pass down the esophagus.

Esophagus: this tube connects the pharynx to the stomach. Where is it relative to the trachea?

behind/around

medulla

cardiac center (heart rate and contractility); respiratory center (depth and rate)

cerebellar white matter (arbor vitae)

carries nerve impulses to other brain areas

vestibulocochlear nerve (cranial nerve VIII)

carries nerve signals to brain

Optic nerves

carry sensory information from the retinas of the eyes (cross over in mammals for depth of field)

lens

changes shape to provide refraction for visual acuity

scansorial

climbing

auditory tube

connects the middle ear cavity with the nasopharynx

brainstem (pons, medulla)

contain centers for control of the heart, blood vessels, and breathing

vitreous humor

contains lens - gives shape to the eye and supports retina

retina

contains rods and cones

cerebellum

contributes to coordination and precision of muscle movements

what animal has true horns

cow

milk teeth name

deciduous

elephant tusk uses

digging, lifting objects, gathering food, stripping bark from trees to eat, and defense

Most mammals are (teeth word) Toothed cetaceans (Odontoceti) are

diphyodont, having two sets of teeth monophyodont, having only one set of teeth

Aqueous humor

distributes nutrients around the front part of the eye as well as eliminating waste products

longitudinal fissue

divides the cerebral hemispheres

Which mammals are homodont, having teeth that are all similar in shape and function? How does feeding style relate to dentition here?

dolphins designed for grasping individual prey items, rather than for chewing

lophodont

elongated ridges between cusps

external auditory canal (meatus)

funnels sound waves to the tympanic membrane

Auricle (pinna)

helps to collect and localize the origin of sound waves

semicircular canals

houses receptors for head movement

cochlea

houses receptors for hearing

vestibule

houses receptors for linear acceleration and gravity

pelvic girdle

ilium, ischium, pubis

saltatorial

jumping

what are rhinoceros horns made of

keratin - not true horns

Which skull(s) do not have canine teeth? Why is there a wide space (diastema)between the anterior teeth and the cheek teeth (molars and premolars) in some of the skulls?

lagomorphs Diastema - holds food in cheek (this is hare and rabbit(?)) so they would be holding/handling food here

Vena Cava goes to

left Atrium?