Anatomy & Physiology 2

Background: The endocrine system comprises many glands (i.e., thyroid, pituitary, hypothalamus, adrenal, thymus, testes, ovaries, pancreas). All these glands play a crucial role in maintaining the everyday activities of our body: homeostasis.

These glands are endocrine glands that secrete chemical messengers (hormones) to the whole body via the bloodstream. Specific receptors will then detect these hormones to trigger particular responses (increasing glucose, sexual hormone production, etc.). The regulations of these hormones released into the bloodstream are complex. One way to regulate the level of hormones is via negative feedback loops so our body is not hypersecreting these powerful messengers.

Learn more about your endocrine system using the figure(s) and video(s) from this chapter and all the lab models.

Background: The cardiovascular system contains the heart, blood and blood vessels (arteries, veins, capillaries, etc.). The heart is located in the pericardial cavity, surrounded by the pericardium membrane. This organ plays the role of a pump activated by the powerful cardiac muscle (myocardium). The heart is regulated via the cardiac conduction system (sinoatrial/atrioventricular nodes and bundle of His). The primary function of this organ is to circulate the blood through the body (systemic & pulmonary circuits).

Blood moves via the veins that carry the blood toward the heart, whereas the arteries transport it away. A network of capillaries will eventually transport blood to "all the corners of our body." 

Using the figure(s) and video(s) from this chapter and all the lab's models, learn more about the anatomy of your heart and the blood vessel structures.

Background: The veins carry the blood toward the heart, whereas the arteries transport the blood away. Blood is distributed everywhere via a network of capillaries. Blood circulation can be divided into two groups: systemic and pulmonary. Fetal blood circulation is slightly different since the lunges are not doing their job yet. First, fetal blood is oxygenated at the placenta and carried by the umbilical veins toward the fetal heart using the ductus venosus. Then the deoxygenated blood is moved to the placenta by umbilical arteries. Fetal circulation also uses the foramen oval, and ductus arteriosus is used by the fetus to shunt the pulmonary circulation blood flow directly within the heart. These two structures disappear shortly after birth.

Besides the blood network, another network is essential for the function of our body, the lymphatic system. This system consists of the lymphatic vessels, lymphatic fluid (i.e., lymph), spleen, thymus, lymphatic nodes, and tonsils (e.g., pharyngeal). The function of the lymphatic system is diverse. It is used to drain the excess tissue fluid and return it to the vascular system, contributes to our immune defenses, and absorbs fats from the digestive system.

Using the figure(s) and video(s) from this chapter and all the lab models, learn more about blood composition and the lymphatic system.

Background: The respiratory system has the primary function of allowing gas exchange, which is essential for all living cells. Cells need oxygen to be supplied to operate and will produce waste like carbon dioxide that needs to be removed. This exchange of gas between the atmosphere and our body is called respiration.

The respiratory system comprises the upper track (i.e., nodes, nasal cavity, pharynx, larynx) and the lower track. The lower track includes two zones: conducting (i.e., trachea, bronchi, and terminal bronchioles) and respiratory (i.e., respiratory bronchioles, alveolar ducts, and alveoli).

The respiration process is three steps story. The first step is pulmonary ventilation which consists of inspiration and expiration. The second step is external respiration which is the gas exchange between alveoli and capillaries. The third step is internal respiration, where the gas exchange occurs between capillaries and cells.

Learn more about your respiratory system using the figure(s) and video(s) from this chapter and all the lab models.

Background: The digestive system mainly breaks down food into nutrients that will be absorbed along the gastrointestinal tract (aka alimentary canal or GI). This system consists of the upper GI tract (i.e., oral cavity, pharynx, esophagus, stomach, and duodenum), lower GI tract (i.e., small and large intestine), and accessory organs. 

There are two types of accessory organs: glands to produce the enzymes (i.e., pancreas, liver, salivary glands) delivered into the lumen of the GI tract and used to break down food. Other accessory organs such as teeth, tongue, and gallbladder are used for chewing, swallowing food, and storing bile.

The double layer of the peritoneum attaches to the organs of the GI tracts. These layers are called the mesentery (i.e., small intestines), the greater omentum and lesser omentum (i.e., stomach, liver), then the falciform ligament (i.e., liver), the mesentery proper, and finally the mesocolon (i.e., colon).

Learn more about your digestive system using the figure(s) and video(s) from this chapter and all the lab models.

Background: The urinary system comprises different parts: kidneys, ureters, urinary bladder, and urethra. This system has many other functions. Its primary role is to filtrate blood from unwanted substances to form urine. The urinary system also regulates blood pH, Ion levels, and blood pressure via the juxtaglomerular apparatus (i.e., granular cells, macula densa), and the elimination of biologically active molecules (e.g., hormones). Finally, the urinary system produces calcitriol and erythropoietin to control calcium levels and stimulate erythrocyte production.

The urinary system contains two kidneys. Each kidney has a bean-shaped form with a concave region called the hilum. Each kidney comprises millions of nephrons, the actual microscopic kidney filtration units. There are two kinds of nephrons: cortical and juxtamedullary. Nephrons will clean our blood from the renal corpuscle to the renal tubule via filtration, reabsorption, and secretion.

Learn more about your urinary system using the figure(s) and video(s) from this chapter and all the lab models.

Background: The female and male reproductive systems share a few general similarities and have apparent differences. The functions of the reproductive system are the production of gametes (secondary oocytes and sperm cells) and the production of hormones (e.g., progesterone and testosterone). The reproductive systems in both sexes are complexes that include the main gonads and accessory organs (such as ducts and other glands). 

The male reproductive system contains two testes. Each testis is in a sac called the scrotum covered by a serous membrane (tunica vaginalis and albuginea). The wall of the scrotum is made of an external layer of skin, a thin layer of fascia, and a layer of smooth muscle (dartos muscle). The scrotum allows the perfect temperature for the development of sperm cells.

Sperm cells are formed in the seminiferous tubules from spermatogonia cells to spermatids via spermatogenesis. Then the spermatid will differentiate via a process called spermiogenesis into sperm cells (spermatozoa). Sperm cells are only one part of the sperm content which will be completed and transported by different accessory structures. The secondary accessory organs of the male reproductive system include ducts (e.g., ejaculatory duct), tubules, prostate, bulbourethral glands, seminal vesicles, and the penis.

Learn more about the male reproductive system using the figure(s) and video(s) from this chapter and all the lab models.

Background: The female and male reproductive systems share a few general similarities and have apparent differences. The functions of the reproductive system are the production of gametes (secondary oocytes and sperm cells) and the production of hormones (e.g., progesterone and testosterone). 

The reproductive systems of both sexes are complex. It includes the main gonads and accessory organs (such as ducts and other glands). The gonads of the female reproductive system are called ovaries and testes in males.

Ovaries are the main gonads of the female reproductive system. The female reproductive system contains different accessory organs like the uterine tubes (or fallopian tubes), uterus, vagina, and mammary glands. The primary function of the female reproductive system is to produce the female gametes called the oocytes and estradiol (female hormone), support fertilization, and assure the development of the embryo and fetus until birth.

Learn more about the female reproductive system using the figure(s) and video(s) from this chapter and all the lab models.