Anatomy Quiz 2

**Synapsids are united by**

**single lower temporal fenestra**

3 major living clades of **mammals**

**Monotremes**

**Metatheria**

**Eutheria**

**Metatheria**→

marsupials

**Eutheria**→

**placental mammals**

**Incus**

derived from quadrate

**malleus**

derived from articular

incus and malleus

2 new bones in the middle ear that are derived from the bones that were ancestrally in the jaw

synapsid synapomorphies

Incus and malleus

hair

mammary glands

**Mammals**

Most basal group of mammals is the **monotremes**, which includes the spiny anteater and platypus

**Marsupials**

united by unusual development and young born very

underdeveloped; these young then attached to nipple and grow, usually within a pouch called a marsupium.

the **tribosphenic molar**

The marsupials are united with placental mammals in the clade **Theria** by a common tooth structure:

**Eutherians**

placental mammals; united by the presence of **chorioallantoic placenta** (vascular connection between young and mother)

Function

how organisms work – depends strongly on movement of organisms and their parts

**functional morphology or**

**biomechanics**

study of organismal function

4 broad factors affect organismal function

a. size

b. material (type and geometry) c. environment \n d. ancestry/phylogeny

**machines**

organisms must withstand and generate forces to move or resist movement; thus, organisms can be examines as **_________** (devices that transfer force) to understand their function

**translation**

change in position

**rotation**

change in orientation

velocity

how fast is an object moving? distance/time = m/s

acceleration

how fast is velocity changing? velocity/time – (m/s)/s

momentum

how much motion has occurred? mass x velocity = kg x m/s

force

how hard is an object to move? mass x acceleration = kg x m/s2 = Newtons

stress

how intensely is a force applied? force/area = N/m2 = Newtons (one direction)

pressure

force/area = N/m2 = Pascals (multiple directions at once)

strains

stresses and pressures produce? change in length/original length

work

what is the effect of the force? (i.e. how far does it move an object?) force x distance = N x m

energy

capacity t work is?

power

how fast is work performed? work/time = (N xm)/s

Newton’s Laws of Motion

a. A body at rest or in uniform motion stays that way unless a force is applied to it b. **F=ma** (!!!!!!!!!!) \n c. **Equilibrium**: when a body exerts a force on another, the second exerts an equal and opposite reaction force

equilibrium

when a body exerts a force on another, the second exerts an equal and opposite reaction force

**vectors**

Forces critical to motion – they are analyzed as **________** with magnitude and direction

**resolved into components**

A force acting at an angle to an object can be **____________________** acting along the axis of the object and perpendicular to the axis of the object

moment

A force (**F**) acting at a distance (**r**) from an object will produce a ___________ that tends to cause the object to rotate. **M=rxF**

moment arm

r is called a ____________

geometrically similar

changes in all size dimensions occur in the same proportion. an increase in length (L) will produce an increase in areas

proportional to L^2, and an increase in volume (and, thus, mass) proportional to L^3.

isometric

As size increases among organisms that are geometrically similar mass (& forces) will increase faster than areas (or resistance to forces)

**allometry**

Organisms may show **changes in shape as well as size** that accommodates disparities in the rates of increase for force and force resistance with size

stress/strain curve

result of material test

strength

maximum stress before “failure”

extensibility

failure strain

failure

*fracture* (breakage) vs. *yield* (irreversible \[i.e “plastic”\] deformation)

stiffness

(E = Young’s modulus of elasticity) = slope of initial linear stress/strain

toughness

work needed to break object (area under stress/strain curve gives index)

tension

pulling along structure axis

compression

squashing along structure axis

shear

sliding of structure layers

torsion

twisting

bending

tension on one side, compression on the other

neutral axis

**Stress** decreases from a maximum at the surface of the structure to zero toward the center of the structure then back to a maximum at the other side (unlike axial tension and compression, in which stresses are equal throughout the structure cross section)

Y

distance from neutral axis to point where stress in calculated

I

**second moment of area (or second moment of inertia**) = index of distribution of material about cross-section

* calculated for bending in a specific direction
* increases as material is placed further from the neutral axis

material and shape

Resistance of structure to loads depends on…

**Safety factor**

degree to which a structure is “overdesigned” relative to the loads is

usually experiences; e.g. failure load/usual load

**Advantages to safety factor**

protects against unpredictable high loads

**limits to safety factor**

cost of maintaining and carrying “extra” material

**mechanical advantage**

To amplify effects of forces exerted, increase L in relative to L out (increases **_______________**)

low velocity

Trade-off for high force

fulcrum

Transmission of force by movements of limb segments at joints can be equated to the movements of arms of levers about a _______

epidermis

superficial

keratinized stratified squamous epithelium

dermis

deep to epidermis

loose connective tissue; dense irregular tissue

hypodermis

superficial fascia; subcutaneous tissue

not part of skin

dendritic cells

stratum spinosum

“langerhans cells”

phagocytes - immune cells

merkel cells

stratum basale

sensory receptors

fingertips, lips, hair base

melanocytes

produce melanin (protein)

hair

small filamentous structures that project from skin surface

epidermis

hair is derived from the __________

shaft and root

hair is composed of 2 main parts

shaft

projects from skin surface

root

embedded in dermis

cuticle cortex and medulla

3 parts of hair from outside to inside

medulla

center of hair

soft keratin

cortex

several layers of keratinocytes

hard keratin

pigment cells

cuticle

superficial layer

overlapping keratinocytes

sweat and sebaceous

2 basic kinds of glands

s. basale

1-2 layers of cells

living cells

s. spinosum

thick layer of cells

living cells

s. granulosum

3-5 layers of cells

living and dead cells

s. lucidum

clear layer

dead cells

only in thick skin (palms, soles)

s. corneum

dead cells

barbules

barbs are heard together by _________

calamus

where blood supply enters in feathers

both thick and thin skin

what types of skin can form a callus

callus

thickening of the s. corneum due to pressure

thick skin

a lot of sweat glands

no hair follicles

“paper towel”

thin skin

hair follicles

sweat glands

sebaceous glands

“printer paper”

involuntary, smooth muscle

arrestor pili muscles have _____ movements caused by __________

fur

longer guard hairs

* modified into quills in some species

dense underfur

horns

dermal bone

covered in keratin sheath (s. basale)

non-shedding

basement membrane

holds epidermis and dermis together

keratin

protein

s. corneum

collagen

= fibrous protein

fibroblast

secrete fibers

macrophages

consume pathogens

adipocytes

fat cells

pigment cells

derived from neural crest cells

chromatophores

melanophores/melanocytes

avascular

skin is ________ except in fishes and amphibians

thin epidermis

fishes

less keratin

unicellular mucous glands

multicellular glands

poison glands

light-producing organs

dentin/enamel

from neural crest cells

hardest bony tissue