Endocrine system

The thyroid gland originates as an evagination from the floor of the pharynx in the region of the developing tongue and moves into the lower neck, eventually losing its connection with the pharynx. The parathyroid glands migrate inferiorly and become associated with the thyroid gland. The pancreas originates as two evaginations from the duodenum, which come together to form a single gland. The adrenal medulla arises from neural crest cells, and the adrenal cortex is derived from mesoderm.

Cardiovascular system

The heart develops from two endothelial tubes, which fuse into a single heart tube. Blood vessels form from small masses of mesoderm that become blood vessels on the outside and blood cells on the inside. These masses fuse to form the cardiovascular system.

Respiratory system

The lungs begin to develop as a single evagination from the foregut in the region of the future esophagus. This evagination branches to form two lung buds. The lung buds elongate and branch, first forming the bronchi that project to the lobes of the lungs and then the bronchi that project to the lobules of the lungs. This branching continues until approximately 17 generations of branching have occurred.

Urinary system

The kidneys develop from mesoderm located between the somites and the lateral portion of the embryo. The urinary system develops in three stages from the head to the tail of the embryo. The ducts join the digestive tract.

Reproductive system

Reproductive system develops in conjunction with the urinary system. Hormones are very important to sexual development of the human.

Ex. 24. Having read the text “Development of the Organ System”, point out the facts that turn out to be new for you.

Ex. 25. Read the beginning of the text “Prenatal Care”. Combine remaining corresponding parts into sentences, paying attention to the meaning of the sentences:

Prenatal care

Prenatal care is the care woman gets during a pregnancy.  Getting early and regular prenatal care is important for the health of both mother and the developing baby. In addition, health care providers are now recommending a woman see a health care provider before she is even trying to get pregnant. 

Health care providers recommend women take the following steps to ensure the best health outcome for mother and baby:

Getting at least 400 micrograms of folic acid every day to help prevent many types of neural tube defects.  Health care providers recommend taking folic acid both before and during pregnancy.

1. Being properly vaccinated for certain diseases (such as chickenpox and rubella) that could harm a developing fetus – _. 2. Maintaining a healthy weight and diet and _. 3. _ before, during, and after pregnancy.

A. getting regular physical activity before, during, and after pregnancy B. it is important to have the vaccinations before becoming pregnant; C. avoiding smoking, alcohol, or drug use.

Ex. 26. Read the following text and list the signs and symptoms of pregnancy:

Signs of pregnancy

Physical symptoms of pregnancy vary. Of the symptoms listed, not all will occur for every woman, and individuals may well experience different symptoms during different pregnancies. The following is a list of the most common symptoms.

First trimester

Breasts may feel swollen, sore, or tender.

Pregnancy sickness may cause nausea and vomiting. It is also known as morning sickness, although it may occur at any time of the day or night.

The sense of smell may be heightened.

Fatigue is a common symptom in early pregnancy. It results from increased progesterone and may be compounded by increased blood volume, which can result in lower blood pressure and lower blood sugar.

Dizziness and fainting may be experienced, particularly after standing up quickly. These symptoms are caused by lower blood pressure and lower blood sugar.

Frequent mild headaches may occur, caused by increased blood circulation

Constipation is a common symptom caused by increased progesterone, which slows the activity of the large intestine.

Increased urination is caused by pressure of the growing uterus against the urinary bladder.

Emotional lability, including dysphoria, crying spells, and mood swings, may be experienced. These mood changes are triggered by the effect of pregnancy hormones on mood regulation in the brain.

Other symptoms may be experienced specifically during the later stages, such as:

Lower backache. Balance and ease of walking may be affected.

Some women report hair loss, others have more body or "facial" hair.

Sensitivity in teeth, higher risk for gum disease may occur.

Some women during pregnancy experience mental disturbances more severe than typical mood swings. Psychological stress during pregnancy is associated with an increase in other pregnancy symptoms.

OVERVIEW

Pregnancy is the term used to describe when a woman has a growing fetus inside of her. Human pregnancy lasts about 40 weeks, or just more than 9 months. Pregnancy is typically divided into three periods, or trimesters, each of about three months. The first 3 months of fetal development are the most important. During this time, all the major organs in the body are formed. The eyes and heart have begun to form. At the end of the sixth week the brain becomes more noticeable, and arm and leg buds begin to appear. By the seventh week, the chest and abdomen are fully formed and the lungs are beginning to develop. During the second trimester the fetus grows and the organs formed during the previous weeks mature. At 13 weeks the fetus can kick and move its toes. The mouth can open and close. The fetus is capable of bending its arms and a fist. Fine hair covers the entire body. The first eyelashes and eyebrows begin to appear. During the third trimester the infant’s eyes are open. Most of the body hair is gone, although the shoulders and arms may still have a light covering.

LESSON 60

CHILD’S DEVELOPMENT