The egg then travels through the oviduct, also called the "fallopian tube." If fertilization occurs, it happens here. Then, the egg travels to the thick-walled, muscular uterus.
When the egg sac matures, its follicle moves to the surface of the ovary, breaks open, and releases the egg.
The two vas deferens empty to the urethra, the same structure through which urine empties. As sperm enter the urethra, the seminal vesicles, Cowper's glands, and the prostate gland secrete fluids into the urethra that nourishes and protects sperm.
Per Utah Code 53G-10-402 parental consent is required prior to teaching this material.
Sperm cells are produced in the seminiferous tubules but then move to the epididymis where they mature and are stored. Mature sperm exit the epididymis through a tube called the "vas deferens."
It's in the uterus that the fetus develops. At the bottom of the uterus is the cervix. That's the opening into the vagina, which leads to the outside of the body.
The zygote then slowly moves through the fallopian tube as it gradually undergoes a series of cell divisions referred to as "cleavage." In the process of cleavage, the zygote repeatedly divides and develops into a ball of cells called a "morula."
Small bronchioles end in tiny air sacs call "alveoli," arranged kind of like grapes on a stem. Alveoli consist of thin membranes lined with a dense network of capillaries across which gas exchange occurs with blood cells.
In the lungs, bronchi branch out into smaller and smaller tubes called "bronchioles."
The diaphragm is a sheet of muscle below the lungs separating the chest cavity from the abdomen. When the diaphragm and the intercostal muscles contract, the size of the chest cavity increases.
Under the ribs in your chest are two very important structures called "lungs." Lungs are the site of gas exchange.
The body responds to these agents by accumulating fluid and debris in the alveoli. This inhibits the ability of the lungs to exchange oxygen. Another relatively common respiratory problem is bronchitis.
Breathing is controlled in a part of the brain generally referred to as the "respiratory center." Feedback is continually given to this part of the brain to adjust the rate of breathing.
The nasal cavity and upper part of the respiratory system is lined with mucus membranes and small hairs that help accomplish these tasks. From the nasal cavity or mouth, air enters the pharynx, or throat.
Smoking makes it difficult for oxygen to be exchanged through alveoli. It's estimated that at least one-third of the smoke inhaled from smoking coats alveoli with particles.
The rock cycle involves the continuous changing of rocks from one form into another form.
The rock cycle is not always straight forward. For example, igneous rocks placed under heat and pressure can become metamorphic rocks, which may be remelted into magma and hardened back into igneous rock.
Diagram demonstrates complexities of the rock cycle, such as sedimentary and igneous rocks melting to form magma.
Diagram illustrating the rock cycle.
Sediments accumulate and compact to form sedimentary rock.
In this line graph, the blue line represents the temperature of the fresh water and the red line represents the temperature of the salt water. According to this graph, the salt water froze at a lower temperature than the fresh water.