Embryology 1-2: Gametogenesis MCQ

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Questions and Answers

What defines the period of the embryo during human development?

From implantation to the 8th week of development (correct)

From birth until the 1st year of life

From fertilization to implantation

From the 8th week until birth

What is the significance of the term 'preimplantation embryo'?

It includes the zygote, morula, and blastocyst stages before implantation (correct)

It refers to the stage after implantation has occurred

It describes the embryo after the 8th week of development

It describes an embryo that has completed its development

How long is pregnancy considered to last when counting from fertilization?

42 weeks

38 weeks (correct)

36 weeks

40 weeks

What does the estimated due date (EDD) calculation typically rely on?

The onset of the last menstrual period (LMP) Signup and view all the answers

What is a challenge when determining the estimated due date based on the last menstrual period?

It assumes a regular menstrual cycle of 28 days Signup and view all the answers

What is the main role of mitochondria in the flagellum of spermatozoa?

To provide energy needed for movement Signup and view all the answers

What is formed from the axoneme of the sperm flagellum?

9 pairs of microtubules surrounding one central pair Signup and view all the answers

What specific function do Sertoli cells perform?

Maintenance of the blood testis barrier Signup and view all the answers

What is a consequence of defects in the axonal structure of sperm?

Defects in sperm motility leading to infertility Signup and view all the answers

How long does the spermatogenic cycle last?

64 days Signup and view all the answers

Which substance does androgen-binding protein bind to assist in the testis?

Testosterone Signup and view all the answers

What is the primary outcome of asynchronous meiosis in the seminiferous tubules?

Different stages of sperm maturation occurring simultaneously Signup and view all the answers

What happens at the end of spermiogenesis?

Spermatids are released into the lumen but are not motile Signup and view all the answers

What is the main function of the theca interna in the follicle?

Production of estrogen precursors and testosterone Signup and view all the answers

What is the significance of the antrum folliculi in ovarian follicles?

It contains liquor folliculi rich in hyaluronic acid. Signup and view all the answers

What characterizes pre ANTRAL (pre Graafian) follicles?

Formation of small intracellular spaces called Cell-Exner bodies Signup and view all the answers

Which hormone stimulates the production of estrogen in granulosa cells?

FSH Signup and view all the answers

What role do fimbriae play during ovulation?

They capture the ovulated complex and guide it into the infundibulum. Signup and view all the answers

What process occurs in the granulosa cells following the synthesis of testosterone by theca interna?

Transformation of testosterone into estrogens Signup and view all the answers

What happens during the slow transport phase in the uterine tube?

Oocytes are given more time in the tube to increase fertilization chances. Signup and view all the answers

What happens to developing follicles in the ovary?

Some follicles degenerate while others enlarge. Signup and view all the answers

What can cause a blockage in the uterine tube?

Inflammation, infections, or endometriosis. Signup and view all the answers

What is found in the liquor folliculi?

Hyaluronic acid and proteins Signup and view all the answers

What is the survival duration of spermatozoa in the female reproductive tract?

80 hours Signup and view all the answers

What is the role of the basal lamina called membrana granulosa?

Barrier against capillaries Signup and view all the answers

Which component does seminal fluid NOT contain?

Hormones to trigger labor Signup and view all the answers

What is the average pH range of seminal fluid?

7.2-7.8 Signup and view all the answers

How long does the rapid transport phase from the isthmus to the uterus take?

8 hours Signup and view all the answers

What is the approximate volume of sperm in an ejaculation?

2-6 ml Signup and view all the answers

What is the primary function of the corpus luteum after ovulation?

To produce hormones to support the endometrium Signup and view all the answers

What characterizes the corpus haemorrhagicum after ovulation?

It results from the collapsing of the corpus luteum Signup and view all the answers

What is one reason why some women experience Mittleschmerz during ovulation?

Enlargement of follicles or slight bleeding in the peritoneal cavity Signup and view all the answers

What happens to the corpus luteum if fertilization does not occur?

It transforms into a menstrual corpus luteum and then a corpus albicans Signup and view all the answers

What component of the ovulated complex aids in the protection of the ovum?

Zona pellucida Signup and view all the answers

What is produced by the syncytiotrophoblast of blastocysts to maintain the function of the corpus luteum?

Human chorionic gonadotropin (HCG) Signup and view all the answers

What is the role of Lgr5+ positive stem cells in ovarian function?

They renovate the ovarian germinative epithelium after ovulation. Signup and view all the answers

What causes the color change in the corpus luteum as it functions?

The increase in vascular network and hormone production Signup and view all the answers

What is the primary reason that spermatozoa have difficulty surviving in the vagina?

The pH of the vagina is very low. Signup and view all the answers

During which phase do some spermatozoa reach the uterus within a short time but are less likely to fertilize an egg?

Fast phase of passage Signup and view all the answers

What change occurs in capacitation that enhances the motility of spermatozoa?

Removal of glycoproteins Signup and view all the answers

What happens to the cervical mucus during ovulation?

It becomes more fluid to facilitate sperm passage. Signup and view all the answers

How long must spermatozoa bind to the isthmus for the capacitation reaction to occur?

24 hours Signup and view all the answers

What role do the cervical crypts play in the sperm passage process?

They store sperm until they can fertilize the egg. Signup and view all the answers

What physiological change is associated with the hyperactivation of spermatozoa?

Improved motility for faster swimming Signup and view all the answers

What effect does the seminal fluid have on the vaginal environment for spermatozoa?

It buffers the acidic environment temporarily. Signup and view all the answers

Study Notes

Human Development

Periods of development: Medical point of view divides development into three trimesters, while embryological perspective distinguishes the period of the egg (zygote to blastocyst), embryo (implantation to 8th week), and fetus (8th week onwards).
Development after birth: Maturation continues after birth, with some systems, like the lungs, developing fully several years later. Aging and senescence are also part of ongoing development throughout life.
Dating pregnancy: Fertilization age is based on calculating weeks from fertilization, which is difficult to determine precisely, (egg and sperm survival times). Estimates based on last menstrual period (LMP) usually consider a 28-day cycle and are thus prone to error.

Dating of pregnancy

Two Methods: Pregnancy can be dated using either fertilization age (difficult to calculate precisely) or by calculating from the onset of the last menstrual period (LMP).
LMP method: This method assumes a 28-day cycle but this is not always the case, which thus leads to inaccuracy in the Estimated Due Date (EDD) calculation.

Developmental Problems

Birth defects: Genetic causes (chromosomal or gene mutations). Environmental influences (drugs, alcohol, infections, chemicals, radiation) and the interaction of these two factors are contributors to birth defects.
Unknown causes: About 50-60% of birth defects have unknown origins.
Susceptibility Periods: The period of greatest susceptibility to major developmental abnormalities lies during weeks 3-8 of development, when organs are forming and rapidly differentiating.

Teratogens

Definition: Teratogens are chemical, physical, or biological agents that cause abnormal fetal development, often with specific effects according to the stage of development at the time exposure occurs.

Phases of Human Embryology

Stages: Stages are gametogenesis, fertilisation, cleavage, gastrulation, morphogenesis, and organogenesis.
Gametogenesis is the process through which gametes (sperm and egg) are formed.
Fertilisation is the fusion of male and female gametes.
Cleavage is the rapid cell division of the zygote (fertilized egg).
Gastrulation occurs after cleavage and organizes into three essential layers for fetal development.
Morphogenesis is the process of arranging of cells into tissues, organs, and body shapes, body plans.
Organogenesis is the development of organs.

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Description

Test your knowledge on human embryology, focusing on the development processes, stages of pregnancy, and the roles of various cell types in reproduction. This quiz covers key concepts from fertilization to spermatozoa function and development. Perfect for students studying developmental biology or related fields.