Embryology

Question 1

The mesoderm that splits into an outer parietal and an inner splanchnic layer is:
a. Dorsal mesoderm
b.Lateral mesoderm
c.Somatic mesoderm
d.Intermediate mesoderm

Answer 1

Lateral mesoderm

Question 2

Which mesoderm becomes organized into somitomeres and somites?
a. Lateral mesoderm
b.Intermediate mesoderm
c.Paraxial mesoderm
d.Splanchnic mesoderm

Answer 2

Paraxial mesoderm

Question 3

Which of the following forms the middle part of each somite?
a.Sclerotome
b.Myotome
c.Syndetome
d.Dermatome

Answer 3

Myotome

Question 4

In which cell cycle phase do neurons permanently function without dividing?
a.G0 phase
b.G1 phase
c.M phase
d.S phase

Answer 4

G0 phase

Question 5

Which organelle is primarily concentrated in the middle piece of a sperm cell?
a.Golgi apparatus
b.Mitochondria
c. Centriole
d.Cytoplasm

Answer 5

Mitochondria

Question 6

Type A, intermediate, and type B are types of:
a.Spermatocytes
b.Spermatozoa
c.Spermatids
d.Spermatogonia

Answer 6

Spermatogonia

Question 7

The acrosome already covers about two-thirds of the condensed nucleus of the spermatid during which phase of spermiogenesis?
a.Maturation phase
b.Acrosome phase
c.Golgi phase
d.Cap phase

Answer 7

Acrosome phase

Question 8

Which cells surround the primary oocyte in a primary follicle?
a.Theca cells
b.Cuboidal granulosa cells
c. Flattened granulosa cells
d.Luteal cells

Answer 8

Cuboidal granulosa cells

Question 9

What notable structural change occurs during the transition of a primary to a secondary ovarian follicle?
a.Formation of the antrum
b.Single layer of granulosa cells
c.Multiple layers of granulosa cells and theca cells
d.Ovulation

Answer 9

Multiple layers of granulosa cells and theca cells

Question 10

The prominent translucent acellular layer which is composed of the condensation of oocyte-secreted glycoproteins is:
a.Membrana granulosa
b.Cumulus oophorus
c. Corona radiata
d.Zona pellucida

Answer 10

Zona pellucida

Question 11

What forms immediately after the rupture of the Graafian follicle during ovulation?
a.Corpus luteum
b.Corpus albicans
c.Corpus hemorrhagicum
d.Corpus cavernosum

Answer 11

Corpus hemorrhagicum

Question 12

For entry into the ovum, the spermatozoa must first pass through the:
a.Vitelline membrane
b.Corona radiata
c.Zona pellucida
d.Theca folliculi

Answer 12

Corona radiata

Question 13

The most reliable criterion that a successful fertilization occurred is:
a.Fusion of the sperm and oocyte membrane
b.Fusion of male and female pronuclei
c.Binding of the sperm to the zona pellucida
d.Digestion of the zona pellucida

Answer 13

Fusion of male and female pronuclei

Question 14

When the yolk of the egg is uniformly distributed through the cytoplasm,
it is classified as:
a.Oligolecithal
b.Centrolecithal
c.Telolecithal
d.Mesolecithal

Answer 14

Centrolecithal

Question 15

Yolk is several times greater than the cytoplasm in which type of egg?
a.Mesolecithal
b.Polylecithal
c. Isolecithal
d.Oligolecithal

Answer 15

Polylecithal

Question 16

The term “morula” refers to which stage of embryonic development?
a.A single-cell zygote
b.A solid ball of cells
c.A hollow ball of cells
d.A multi-layered structure

Answer 16

A single-cell zygote

Question 17

What is the main function of the trophoblast in early embryonic
development?
a.Formation of the embryo proper
b.Formation of extraembryonic membranes
c.Nutrient absorption
d.Waste elimination

Answer 17

Formation of extraembryonic membranes

Question 18

In avian species, the embryo will develop in the:
a.Blastocoele
b.Area opaca
c.Area pellucida
d.Yolk

Answer 18

Area pellucida

Question 19

The funnel shape depression of the Hensen’s node is called:
a.Primitive pit
b.Primitive ridge
c.Primitive groove
d.Primitive streak

Answer 19

Primitive pit

Question 20

Hydrops occurs most often in which of the following domestic
species?
a.Pig
b.Horse
c.Sheep
d.Cattle

Answer 20

Cattle

Question 21

Which stage of embryonic development implants into the uterine wall?
a.Gastrula
b.Zygote
c.Blastula
d.Morula

Answer 21

Blastula

Question 22

When the blastocyst burrows through the uterine epithelium to the uterine stroma and becomes completely cut off from the uterine lumen, the implantation is said to be:
a.Centric
b.Eccentric
c.Superficial
d.Interstitial

Answer 22

Interstitial

Question 23

The embryonic disc in mammals is composed of which two layers?
a.Trophoblast and inner cell mass
b.Epiblast and hypoblast
c.Ectoderm and mesoderm
d.Endoderm and mesoderm

Answer 23

Epiblast and hypoblast

Question 24

Which organ system is the first to develop in the mammalian embryo?
a.Respiratory
b.Circulatory
c.Nervous
d.Digestive

Answer 24

Nervous

Question 25

Which of the following brain vesicles remain undivided during embryonic development? a.Mesencephalon b.Telencephalon c.Prosencephalon d.Metencephalon

Answer 25

Mesencephalon

Question 26

Rhombic lips are the first evidences of the embryonic development of which organ? a.Cerebrum b.Cerebellum c. Hypophysis cerebri d.Corpora quadrigemina

Answer 26

Cerebellum

Question 27

The neural crest cells migrate to form various structures EXCEPT: a.Central nervous system b.Facial cartilage and bones c.Adrenal medulla d.Peripheral nervous system

Answer 27

Central nervous system

Question 28

The process of gastrulation results in the formation of which structure? a.Blastocoele b.Neural tube c.Germ layers d.Somites

Answer 28

Germ layers

Question 29

Which of the following structures is a derivative of the endoderm? a.Adrenal cortex b.Oviduct c.Axial and limb muscles d.Pancreas

Answer 29

Pancreas

Question 30

Which of the following bone is formed by desmal ossification? a.Humerus b.Tibia c. Cervical vertebrae d.Occipital bone

Answer 30

Occipital bone

Question 31

What process of programmed cell death shapes the digits during limb development? a. Patterning b.Differentiation c. Morphogenesis d.Apoptosis

Answer 31

Apoptosis

Question 32

The embryonic precursor to the mammalian kidney is the: a. Pronephros b.Mesonephros c. Metanephros d.All of these

Answer 32

Metanephros

Question 33

The ureteric bud does NOT contribute to the formation of which structure? a. Renal pelvis b.Glomerulus c. Collecting duct d.Ureter

Answer 33

Glomerulus

Question 34

The primitive gut tube is divided into foregut, midgut, and hindgut based on: a. Blood supply b.Length of the tube c. Neural crest cell migration d.Rotation of the tube

Answer 34

Blood supply

Question 35

Which of the following adult structures originated from the embryonic foregut? a. Jejunum b.Liver c. Cecum d.Cloaca

Answer 35

Liver

Question 36

Which structure is responsible for the development of the adenohypophysis? a. Proctodaeum b.Infundibulum c. Rathke’s pouch d.Otic placode

Answer 36

Rathke’s pouch

Question 37

The pharyngeal pouches contribute to the development of the: a. Heart b.Ears c. Adrenal gland d.Parathyroid gland

Answer 37

Parathyroid gland

Question 38

In which part of the mammalian embryo does hematopoiesis first occur? a. Liver b.Bone marrow c. Spleen d.Yolk sac

Answer 38

Yolk sac

Question 39

Which part of the adult heart is formed by the sinus venosus? a. Right atrium b.Left atrium c. Right ventricle d.Left ventricle

Answer 39

Right atrium

Question 40

In the developing heart, the atrioventricular (AV) canal is partitioned by which structure? a.Endocardial cushions b.Bulbus cordis c. Foramen ovale d.Truncus arteriosus

Answer 40

Endocardial cushions

Question 41

Which structure forms the precursor to the vertebral column? a. Primitive streak b.Neural tube c. Sclerotomes d.Notochord

Answer 41

Notochord

Question 42

In the developing eye, the optic vesicle induces the overlying ectoderm to form the: a. Retina b.Cornea c. Lens d.Sclera

Answer 42

Lens

Question 43

Which of the following stages of lung development establishes the bronchioles and terminal bronchioles? a. Canalicular b.Alveolar c. Saccular d.Pseudoglandular

Answer 43

Pseudoglandular

Question 44

Which embryonic structure is the primordia to the mammalian lung? a. Tracheoesophageal groove b.Respiratory diverticulum c. Alveolar buds d.Septum transversum

Answer 44

Respiratory diverticulum

Question 45

Barker foal syndrome results from lack of production of pulmonary surfactant by which type of cells? a. Type I pneumocytes b.Type II pneumocytes c. Alveolar macrophages d.Endothelial cells

Answer 45

Type II pneumocytes

Question 46

The amnion primarily functions to: a. Exchange gases b.Provide nutrients c. Protect the embryo d.Remove waste

Answer 46

Protect the embryo

Question 47

How many tissue layers are there in a synepitheliochorial type of placenta? a. 3 b.4 c. 5 d.6

Answer 47

5

Question 48

Specialized microzones of chorionic villi known as microcotyledons characterize the placenta of: a.Cattle b.Cat c.Horse d.Pig

Answer 48

Horse

Question 49

The embryonic paramesonephric ducts will develop into which of the following structures? a. Vulva b.Vagina c. Ductus deferens d.Ductus epididymis

Answer 49

Vagina

Question 50

The formation of the mammalian diaphragm is primarily influenced by the: a. Septum transversum b.Septum secundum c. Septum intermedium d.Septum primum

Answer 50

Septum transversum