Anatomy Final Review Questions

What are unique characteristics of synapsids?

Terrestrial vertebrates, single pair of lateral skull openings (fenestra), heterodont teeth (different teeth shapes), limbs beneath the body

What are two groups of synapsids?

Eupelycosaurs and therapsids

What are some traits of eupelycosaurs?

Carnivores, 2 types of teeth, quadrupedal, dorsal sail

What species is an example of a eupelycosaur?

Dimetrodon

What are some traits of therapsids?

Larger temporal fenestra, both carnivores and herbivores, more differentiated teeth, more movement in the limbs (flexibility)

Therapsids can be roughly divided into non-cynodont and cynodont groups. What are some traits of non-cynodont therapsids?

Increased metabolic rate, expanded dentary bone (lower jaw bone with teeth), incomplete secondary pallate, very diverse

What are two examples of non-cynodont therapsids?

Dinocephalins and gorgonopsids

What are unique traits of cynodonts?

Complete secondary pallate (separate breathing and eating spaces), nasal turbinates, calcaneal heel, no lumbar ribs, lumbar vertebrae, diaphragm (aspiration pump)

What is significant about the loss of ribs that occurs with the evolution of lumbar vertebrae?

Lumbar vertebrae do not have ribs (losing ribs means loss of intercostal muscles- respiration). There was not a decrease in the demand for oxygen, so there must be a functional replacement for those lost muscles. This is the diaphragm. Therefore, the loss of ribs indicates the presence of a diaphragm where we are switching from a costal pump to an aspiration pump.

What characteristics of mammals relate to the lower jaw? How do they relate to each other?

•  1 joint between dentary and squamosal bone (dentary bone- mandibular part, squamosal- cranial connection) → Dentary Squamosal Joint

• Mammalian middle ear- stapes (seen in amphibians, independent from jaw), malleus (formed from articular bone), incus (formed from quadrate bone)

• Angular bone supports tympanic membrane (eardrum)

How does the mammalian trait of feeding babies with milk relate to the evolution of muscles of facial expression?

Mammals can suck and breathe at the same time because of the complete secondary palate that first evolved in cynodonts. It is this ability that allows mammals to suckle, which is a defining feature for the group. In order to suckle, newborn mammals need a greater range of movement around the mouth. This led to the evolution of specialized
groups of muscles (the orbicularis oris and zygomaticus). These muscles allow for suckling but also allow evolved into the muscles of facial
expression

Define “hormone”

A chemical messenger secreted into the blood by an endocrine gland and affecting a
target tissue

Define “endocrine gland”

A gland that secretes its product directly into the bloodstream

Where in the vertebrate body does the thyroid gland develop?

Floor of the pharynx

What element is key in the production of the hormones produced by the thyroid gland?

Iodine

Where are the parathyroid glands located in mammals?

In or near the thyroid

What is the name of the hormone produced by the parathyroid glands and what element does it effect?

Parathyroid hormone (parathormone). It affects calcium metabolism

Where are the adrenal glands located in the vertebrate body?

On the cranial aspect of the kidneys (on top)

What are the two types of cells present in the adrenal glands and what type of hormone does each type produce?

• Adrenocortical cells produce corticosteroids (mineralocorticoids, glucocorticoids, and
  androgens)

• Chromaffin cells produce catecholamines

What are the names of the two regions of the pituitary gland?

Neurohypophysis and aIslets of Langerhansdenohypophysis

Where are the endocrine cells of the pancreas located?

Islets of Langerhans

List the hormones produced by each of these pancreatic cell types: Alpha cells, Beta cells, Delta cells, and PP cells

Alpha cells - glucagon

Beta cells - insulin

Delta cells - somatostatin

PP cells –pancreatic polypeptides

How do the terms “endocrine” and “exocrine” relate to the mammalian pancreas?

Endocrine – A gland that secretes its product directly into the blood to affect other organs
Exocrine – A gland that secretes its product through a duct or opening to a body surface
The pancreas is both an endocrine and an exocrine gland. Its endocrine products
include insulin which affects blood sugar. Its exocrine products are digestive enzymes that are secreted into the duodenum.

What are the three groups of living mammals?

Prototherians (monotremes), metatherians, and eutherians

What are some defining traits of monotremes?

Lay eggs, males have spurs on their hindlegs, milk is secreted directly onto the skin

What is an example of a monotreme?

Platypus

Define “therian”

Mammals with placentas

What are some defining traits of marsupials?

Pouch (for carrying), birth occurs early in development, choriovitelline placenta, epipubic bones

What is an example of a marsupial?

Kangaroo, opossum, sugar glider

What are some defining traits of eutherians?

Long development in the uterus (no pouch), no epipubic bones, chorioallantoic placenta

What is an example of a eutherian?

Cattle, dog, squirrel, human

Australian marsupials are very like many species of placental (eutherian) mammals. However, there are no marsupial equivalents of cetaceans (whales and dolphins) or even seals. Why?

There are no marsupial (ex. kangaroo) equivalents of cetaceans (whales/dolphins) because a defining trait of a marsupial is their pouch. Cetaceans like whales and dolphins live underwater and even though the pouch can close in some cases, it can never be completely watertight. The pouch is not a feature that is adapted well to an aquatic environment, so this is not something we would see in animals like whales or dolphins.

Be able to read a dental formula

Mammal tooth groups- molars (m), canines (c), incisors (i), premolars (p)

 

Dental formula example: I^5/4 C^1/1 P^3/3 M^1/1 (Tooth ^upper/lower)  upper = 5+1+3+1 = 10 ; lower = 4+1+3+1= 9 (total = 19 x 2 = 38 teeth)

List the two main parts of the nervous system and which structures are associated with each part.

Central nervous system – brain and spinal cord
Peripheral nervous system – spinal nerves, cranial nerves and their ganglia

List the three main sections of the mammalian brain

Forebrain, midbrain, and hindbrain

Identify which portion of the brain houses the reflex center for respiration

Hindbrain (medulla oblongata)

Identify which portion of the brain maintains equilibrium

Hindbrain (cerebellum)

Differentiate between the sympathetic and parasympathetic nervous systems

The sympathetic nervous system upregulates the body (fight or flight)

• Increases heart rate

• Increases respiratory rate

• Increases blood glucose

• Pupils dilate

The peripheral nervous system downregulates the body (rest and digest)

• Decreases heart rate

• Decreases respiratory rate

• Stimulates the digestive tract

• Pupils constrict

Be able to describe which parts of the central nervous system in general are responsible for sensory reception and coordination and which are responsible for motor coordination and output.

Sensory input: received and coordinated in the dorsal portions of the
central nervous system (the dorsal horn of the spinal cord and the tectum of the
midbrain)
Motor output: coordinated in the ventral portions of the central nervous
system (the ventral horn of the spinal cord and the tegmentum of the midbrain)

What are the anatomical traits of primates?

Diverse, shortened muzzle, forward facing eyes, large brain:body size ratio, prehensile hands (with opposable thumbs) and feet, nails, pads on fingertips

What is an example of a strepsirrhine primate?

Lemur

What is an anatomical feature that strepsirrhines have that affects their sense of smell? Do haplorrhine primates have this structure?

Rhinarium; haplorrhines don’t have this

What types are primates are included in the Hominidae?

Great apes- orangutans, gorillas, chimpanzees, bonobos, and humans

What are the unique traits of hominid primates?

Large body size, males are larger than females, lack ischial callosities

What is unique about the pelvis of Ardipithecus?

It shows adaptations combining tree climbing and bipedalism

What is unique about the toes of Ardipithecus?

They have a rigid foot with a grasping big toe

What features of Australopithecus support bipedalism?

Foramen magnum positioned ventrally, short, broad pelvis, knees positioned over the ankles, lack of opposable big toes

Lucy is the most famous specimen of Australopithecus afarensis. What features of Lucy’s skeleton indicate that she was an adult?

We know that Lucy was an adult because her growth plates had fused, she had sutures in her skull that were fused, and her wisdom teeth had both erupted and were worn down (this means she had been using them to chew).

List the unique features of the skull of Paranthropus species

Prominent brow ridge, flaring cheekbones, pronounced sagittal crest, large jaws, very large molars

What is special about the teeth of Paranthropus? What does this indicate about their diet?

The molars are very large and have the thickest enamel of any known
early human. This indicates that they were herbivores and they needed to generate a lot of jaw force indicating that seeds, nuts, and tough vegetation were a part of their diet.

Which species of Homo first showed evidence of eating meat?

Homo habilis

Which species Homo first showed body proportions similar to those of modern humans?

Homo erectus

What four innovations are associated with Homo erectus?

1. Hand axes

2. Caring for old and weak group members

3. Campfires

4. Leaving Africa

What is the scientific name of the species nicknamed “hobbits”?

Homo floresiensis

What is the definition of insular dwarfism?

The process of large animals evolving a reduced body size due to being in a restricted environment (ex. island)

What are unique anatomical characteristics of Homo neanderthalensis?

Shorter and stockier than modern humans, heavy brow ridge, large noses oval shaped skulls

What social innovations began with Homo neanderthalensis?

Wearing clothes and burying the dea

What features differentiate the skulls and skeletons of Homo sapiens from other species of Homo?

Lighter skeleton, high vaulted skull (increased cranial capacity), flat forehead, smaller jaws and teeth

What parts of the skeleton have changed in adaptation to bipedalism?

Foramen magnum, spine, pelvis, legs, and foot

What is the functional significance of the S-shaped bend in the vertebral column of Homo sapiens?

The bend places the center of gravity of the body directly above the hips. When the
knees are held straight, the leg bones transmit the weight of the body to the ground
and the base of support formed by the area of contact between the feet and the
substrate lies directly beneath the center of gravity. As a result, the leg bones support
the weight of the body, and little muscular effort is required for a human to stand
erect.

How is the shape of the pelvis different in bipeds as compared to quadrupeds?

Bipeds- broad and bowl shaped

Quadrupeds- box like

What are two changes in the bones of the legs related to bipedalism?

The femurs angle medially, and the knees are positioned over the ankles. In the feet,
the calcaneus is prominent, the metatarsals arch, and the big toe is parallel to the
other toes rather than opposable

What are two ways that tool use could have affected brain size?

1. Stimulation of portions of the brain associated with visual-motor coordination and
   planning

2. Availability of a higher quality diet

Which three structures changed in the evolution of spoken language?

1. Larynx

2. Hyoid

3. Ear

How is the position of the larynx different in the human throat as compared to that of the chimpanzee?  What risks are associated with this change?

The human larynx is descended further into the throat. This increases the risk of choking.

What sounds are associated with this change?

Vowels

What are the functions of Broca’s area in the human brain?

Broca’s area regulates breathing patterns for speech and controls the vocalizations
required for normal speech

What are the functions of Wernicke’s area in the human brain?

Wernicke’s area is involved in speech comprehension

Define “prevalence”

The total number of cases of a disease in a particular population at a given time

Define “congenital”

A medical condition present and existing at the time of birth

What parts of the body are affected by Chiari malformations?

Skull, the foramen magnum, and the cerebellum

What are the four changes of the heart that occur in Tetralogy of Fallot? In combination, what is the effect of these changes?

1. Ventral septal defect

2. Pulmonary stenosis

3. Enlarged aortic valve

4. Ventricular hypertropy

Mixing of oxygenated and deoxygenated blood, blood has overall lower oxygen concentration.

Besides humans, in which other species has Tetralogy of Fallot been reported?

Dogs, horses, cats

Define “hip dysplasia”

Abnormal formation of the hip joint where the acetabulum does not completely cover the head of the femur

Suppose that Bigfoot (Sasquatch, an imaginary primate alleged to live in the Pacific Northwest) or the Yeti (an equally imaginary primate that is supposed to live in the Himalayas) was found to be real and to be a derived descendant of Homo erectus. What moral responsibility would we (Homo sapiens) have to a species that was as closely related to us as a coyote is to a dog? Would we feel less responsible if it was more closely related to another species of great ape?

I think that because of our social relationships and highly developed emotions, we would feel a moral responsibility to try to make contact with this species and explore what it would be like to connect with a species that is closely related to us. I think we would feel less responsible if it was a more distant descendant because we would likely not have as much in common with that species.