General Biology - NCLEX-PN

Gastrin is produced by the G cells of the stomach. Parietal cells of the stomach secrete hydrochloric acid, while chief cells secrete pepsinogen and chymosin. Beta-islet cells of the pancreas produce glucagon.

Gastrin, a peptide hormone released by G-cells of the stomach, has many functions in digestion. It triggers parietal cells to release , it increases gastric motility, it triggers chief cells to secrete pepsinogen, and it stimulates the gallbladder to release bile.

is secreted by parietal cells of the stomach. Chief and foveolar cells of the stomach secrete pepsinogen and mucus respectively, and M cells are not stomach cells, but rather intestinal cells involved in mucosa-associated lymphoid tissues, or MALT.

Amylase enzymes, produced by the salivary gland and the pancreas, break starched down into simple sugars. Peptidase and protease enzymes break down proteins, while lipase enzymes break down lipids.

The hydrolysis of oligosaccharides into disaccharides occurs in the duodenum, after the addition of pancreatic amylase from the pancreatic duct.

The intestinal brush border is the microvilli-covered surface of the small intestine. It is where a large part of the digestive process occurs, aided by brush-border enzymes such as sucrase, maltase, lactase, and carboxypeptidase.

Stomach transit time varies widely: it can take anywhere from ten minutes to four hours for food to pass through the pyloric sphincter into the duodenum. Transit time in the stomach is affected by the composition of the meal, and by the individual's rate of gastric emptying. Transit time may be shortened due to consumption of liquid or simple-carbohydrate foods, or lengthened in the case of consumption of solid food that has a high protein or fiber content.

Normal transit time of food through the small intestine is three to eight hours. This is significantly longer than transit time through the stomach due to the wider variety of digestive processes that occur in the small intestine, including the catabolism of proteins, lipids, nucleic acids, and simple and complex carbohydrates.

Long bones are lengthened during childhood and adolescence via a process referred to as endochondral ossification. In this process, chondrocytes of the growth plate hypertrophy and eventual die, leaving cavities that are then colonized by osteoprogenitor cells. These osteoprogenitor cells then differentiate into osteoblasts, which mineralize the newly forming bone. None of the other answers are actual processes in bone formation or physiology.

There are five distinct zones in regions of endochondral ossification. These are the resting zone, the zone of proliferation, the zone of maturation, the zone of calcification, and the zone of ossification.

The average colon transit time for both adults and children is between 32 and 48 hours. This is significantly longer than the transit times of food through the stomach and small intestine, which averages 4-12 hours total. A slow transit time through the colon can be increased by various lifestyle factors such as exercise and hydration, and dietary changes such as an increase in fiber-rich foods and avoidance of food allergies or other constipation triggers.

The main artery supplying blood to the small intestine is the superior mesenteric artery. This vessel branches off the abdominal aorta and supplies the lower part of the duodenum, the ileum, the jejunum, and two-thirds of the transverse colon. The rest of the colon and the rectum are supplied by the inferior mesenteric artery, while the right hepatic and left gastric supply the liver and stomach, respectively.

We have three main types of salivary glands: the parotid glands, the submandibular glands, and the sublingual glands. The thymus gland is not a salivary gland, and is located in the chest just superior to the heart.

The head of the femur articulates with the acetabulum, a concave surface on the pelvis formed by the union of three bones: the ilium, the ischium, and the pubis.

The obturator foramen is a large opening in the pelvis formed by the pubis and the ischium bilaterally. It does not form any joints but rather allows the passage of the obturator artery, nerve, and vein.

The glenoid fossa is the surface onto which the head of the humerus articulates in the shoulder, and the patella is a part of the knee.

Bursae are synovial fluid sac between bones and overlying tissues. They provide a cushion between the bone and tendons or musculature around them, allowing for reduced friction and painless movement.

A tendon is a connective tissue point of attachment of muscle to bone, while a ligament is a connective tissue attachment from bone to bone. A capsule is a fibrous, fluid filled structure surrounding a synovial joint.

Bruxism, or involuntary tooth grinding, can cause inflammation and damage in the temporomandibular joint, which is the articulation between the condyle of the mandible and the temporal bone.

The xiphisternal joint is between the xiphoid process and the body of the sternum. The intermetacarpal joints are formed between the metacarpal bones of the hand, and the pisotriquetral joint is between the pisiform and triquetrum of the wrist.

Movement along a sagittal plane that decreases the angle between bones is flexion. This is in contrast to extension, which is movement along a sagittal plane that increases the angle between bones. Adduction is movement that pulls a structure toward the midline of the body, while abduction moves a structure away from midline.

Circumduction is movement that produces a circular motion wth the distal end of a body part. True circumduction allows for a 360 degree range of movement. Of the joints listed, the only one capable of circumduction is the shoulder.

Condyloid joints are a form of synovial joint in which a condyle rests in an ovoid cavity. Of the joints listed, the only condyloid joint is the metacarpophalangeal joints (the joint of the most proximal knuckle).

The acromioclavicular joint is a plane joint, while the glenohumeral and humeroradial joints are both ball and socket joints.