Search Encyclopedia The uterus is an organ. It is part of the female reproductive system. It's where an egg is fertilized and a baby grows. You may know it as the womb. The uterus is hollow and pear-shaped. It is about the size of a fist. It's in your lower belly (pelvic area). Your uterus is connected to your fallopian tubes. These tubes help carry eggs from your ovaries into the uterus. The lower part of the uterus connects to the vagina and is called the cervix. The wider, upper part of the uterus is called the corpus or fundus. The uterus has 3 layers:
In women who still have their periods, 1 ovary releases an egg into a fallopian tube each month. During this time, the endometrium becomes thicker to prepare for a fertilized egg. The egg enters the uterus. If it isn’t fertilized, it leaves the uterus through the vagina and the endometrial lining is shed during your menstrual period. If the egg joins with a male sperm cell, this fertilized egg attaches to the endometrium. The thick wall of the uterus protects the growing baby during pregnancy. During labor, the cervix opens (dilates). The muscles of the myometrium help push the baby out through the vagina. The balance of the female hormones estrogen and progesterone control this process. Your ovaries make most of these hormones. Medical Reviewers:
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What does the uterus look like?One of the most recognised changes in a pregnant woman’s body is the appearance of the ‘baby bump’, which forms to accommodate the baby growing in the uterus. The primary function of the uterus during pregnancy is to house and nurture your growing baby, so it is important to understand its structure and function, and what changes you can expect the uterus to undergo during pregnancy. The uterus (also known as the ‘womb’) has a thick muscular wall and is pear shaped. It is made up of the fundus (at the top of the uterus), the main body (called the corpus), and the cervix (the lower part of the uterus ). Ligaments – which are tough, flexible tissue – hold it in position in the middle of the pelvis, behind the bladder, and in front of the rectum. The uterus wall is made up of 3 layers. The inside is a thin layer called the endometrium, which responds to hormones – the shedding of this layer causes menstrual bleeding. The middle layer is a muscular wall. The outside layer of the uterus is a thin layer of cells.  The size of a non-pregnant woman's uterus can vary. In a woman who has never been pregnant, the average length of the uterus is about 7 centimetres. This increases in size to approximately 9 centimetres in a woman who is not pregnant but has been pregnant before. The size and shape of the uterus can change with the number of pregnancies and with age. How does the uterus change during pregnancy?During pregnancy, as the baby grows, the size of a woman’s uterus will dramatically increase. One measure to estimate growth is the fundal height, the distance from the pubic bone to the top of the uterus. Your doctor (GP) or obstetrician or midwife will measure your fundal height at each antenatal visit from 24 weeks onwards. If there are concerns about your baby’s growth, your doctor or midwife may recommend using regular ultrasound to monitor the baby. Fundal height can vary from person to person, and many factors can affect the size of a pregnant woman’s uterus. For instance, the fundal height may be different in women who are carrying more than one baby, who are overweight or obese, or who have certain medical conditions. A full bladder will also affect fundal height measurement, so it’s important to empty your bladder before each measurement. A smaller than expected fundal height could be a sign that the baby is growing slowly or that there is too little amniotic fluid. If so, this will be monitored carefully by your doctor. In contrast, a larger than expected fundal height could mean that the baby is larger than average and this may also need monitoring. As the uterus grows, it can put pressure on the other organs of the pregnant woman's body. For instance, the uterus can press on the nearby bladder, increasing the need to urinate. How does the uterus prepare for labour and birth?Braxton Hicks contractions, also known as 'false labour' or 'practice contractions', prepare your uterus for the birth and may start as early as mid-way through your pregnancy, and continuing right through to the birth. Braxton Hicks contractions tend to be irregular and while they are not generally painful, they can be uncomfortable and get progressively stronger through the pregnancy. During true labour, the muscles of the uterus contract to help your baby move down into the birth canal. Labour contractions start like a wave and build in intensity, moving from the top of the uterus right down to the cervix. Your uterus will feel tight during the contraction, but between contractions, the pain will ease off and allow you to rest before the next one builds. Unlike Braxton Hicks, labour contractions become stronger, more regular and more frequent in the lead up to the birth. How does the uterus change after birth?After the baby is born, the uterus will contract again to allow the placenta, which feeds the baby during pregnancy, to leave the woman’s body. This is sometimes called the ‘after birth’. These contractions are milder than the contractions felt during labour. Once the placenta is delivered, the uterus remains contracted to help prevent heavy bleeding known as ‘postpartum haemorrhage‘. The uterus will also continue to have contractions after the birth is completed, particularly during breastfeeding. This contracting and tightening of the uterus will feel a little like period cramps and is also known as 'afterbirth pains'. Read more here about the first few days after giving birth. Which tissue in the wall of the uterus is required for labor contractions elastic cartilage stratified squamous skeletal muscle?Smooth muscle cells are responsible for involuntary contractions and are found in the walls of blood vessels and hollow organs such as the gastrointestinal tract, uterus , and bladder.
Which tissue would line the uterine tubes and function as a conveyor belt to help move a fertilized egg towards the uterus?There are, on the surface of the fimbria, microscopic hairs called cilia, which constantly beat in the direction of the uterus at a fantastically rapid speed and create a kind of conveyor-belt effect for moving the egg into the tube and toward the uterus.
Which tissue would line the uterine?The uterus has a muscular outer layer called the myometrium and an inner lining called the endometrium.
Which tissue would line the uterine tubes and function as a conveyor belt?Ciliated columnar epithelium is composed of simple columnar epithelial cells with cilia on their apical surfaces. These epithelial cells are found in the lining of the fallopian tubes and parts of the respiratory system, where the beating of the cilia helps remove particulate matter.
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Which tissues in the wall of the uterus is required for labor contractions?
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