TEAS Test of Essential Academic Skills - Set 3 - Part 3

Correct Answer: Glomerulus

The glomerulus is a tuft of capillaries inside Bowman's capsule. High capillary pressure forces water and small solutes from the blood into the capsule, beginning urine formation. Option a is incorrect because the loop of Henle establishes the medullary concentration gradient that allows urine concentration; it is a site of reabsorption, not initial filtration. Option b is incorrect because the proximal convoluted tubule is responsible for most reabsorption of water, glucose, and ions from the filtrate, not initial blood filtration. Option c is incorrect because the distal convoluted tubule fine-tunes electrolyte balance and pH under hormonal control; it acts after filtration has already occurred.

Correct Answer: Urethra

The urethra is the tube that carries urine from the bladder to the outside of the body. It is shorter in females than in males, where it also serves reproduction. Option a is incorrect because the renal artery delivers blood to each kidney for filtration; it is a vascular supply, not a urinary drainage tube. Option b is incorrect because the ureter carries urine from each kidney to the bladder; it brings urine into the bladder rather than out of the body. Option d is incorrect because the renal vein returns filtered blood from the kidney to the inferior vena cava; it does not transport urine.

Correct Answer: Innate immunity

Innate immunity provides general, fast defense against any threat. It includes physical barriers like skin, chemical defenses such as gastric acid, and cellular defenses like neutrophils and macrophages. Option b is incorrect because humoral immunity is part of adaptive defense involving B cells producing antibodies against specific antigens; it is slower and pathogen-specific. Option c is incorrect because cell-mediated immunity is also part of adaptive defense, involving specific T cell responses to infected cells, not generalized first-line protection. Option d is incorrect because adaptive immunity is specific to particular antigens and develops more slowly; it is not the body's immediate generalized first line of defense.

Correct Answer: B lymphocytes

Activated B lymphocytes differentiate into plasma cells that produce large amounts of antibody specific to a particular antigen. Antibodies neutralize, opsonize, or activate complement against the target. Option a is incorrect because helper T cells coordinate immune responses by activating B cells and other T cells, but they do not themselves manufacture antibody molecules. Option b is incorrect because cytotoxic T cells directly kill infected or abnormal body cells; they do not differentiate into plasma cells or produce antibodies. Option c is incorrect because macrophages engulf pathogens and present antigens but do not become plasma cells; antibody production is a B cell function.

Correct Answer: Coordination of adaptive immunity

Helper T cells coordinate adaptive immunity by activating B cells and cytotoxic T cells. As HIV destroys helper T cells, the orchestration of antibody and cell-mediated responses fails progressively. Option a is incorrect because stomach acid production is a function of parietal cells in the gastric mucosa and is unrelated to helper T cell counts in immunity. Option b is incorrect because the cough reflex is a respiratory and neural response coordinated by the brainstem, not a function dependent on helper T cell activity. Option d is incorrect because ciliary movement in airways is a structural and mechanical defense by epithelial cells; it does not require helper T lymphocytes.

Correct Answer: Redness, heat, swelling, pain, loss of function

The five classic signs of inflammation are redness, heat, swelling, pain, and loss of function. They reflect vasodilation, increased permeability, and stimulation of pain receptors at the site. Option a is incorrect because cough, fatigue, sweating, fever, and weight loss are systemic symptoms of conditions like infection or cancer, not the local signs of inflammation. Option c is incorrect because nausea, vomiting, diarrhea, cramping, and fever are gastrointestinal symptoms and not the classic local signs of tissue inflammation. Option d is incorrect because bruising, bleeding, dizziness, tingling, and fatigue describe a mix of bleeding and neurological symptoms, not the classic inflammatory response.

Correct Answer: Osteoclast

Osteoclasts are large multinucleated cells that resorb bone matrix. By breaking down bone, they release calcium and phosphorus into the bloodstream and allow bone remodeling to occur. Option b is incorrect because osteoblasts build new bone by laying down collagen and mineral matrix; they oppose, rather than perform, bone breakdown and mineral release. Option c is incorrect because osteocytes are mature bone cells trapped in the matrix that maintain bone tissue; they do not actively resorb bone or release minerals on their own. Option d is incorrect because chondrocytes are cartilage cells that maintain cartilage matrix; they do not break down bone or contribute to mineral release into blood.

Correct Answer: Ball-and-socket joint

A ball-and-socket joint, such as the shoulder or hip, allows the greatest range of motion. Its rounded head fits into a cup-shaped socket, permitting movement in all planes. Option a is incorrect because a hinge joint, like the elbow or knee, allows movement in only one plane through flexion and extension, not movement in all planes. Option b is incorrect because a pivot joint allows rotation around a single axis, such as between the first two cervical vertebrae; it does not allow multiplanar motion. Option c is incorrect because a saddle joint, such as the thumb base, permits biaxial movement but not full rotation in every plane like a ball-and-socket joint.

Correct Answer: Axial skeleton

The axial skeleton consists of the skull, vertebral column, and thoracic cage including the sternum and ribs. It contains eighty bones forming the central axis of the body. Option a is incorrect because the appendicular skeleton includes the limbs and their girdles; it does not contain the skull, vertebral column, sternum, or rib cage. Option b is incorrect because the pelvic girdle is part of the appendicular skeleton attaching the lower limbs to the axial skeleton; it does not include the skull or ribs. Option d is incorrect because the pectoral girdle is part of the appendicular skeleton attaching the upper limbs; it consists of the clavicle and scapula only.

Correct Answer: Ligament

Ligaments are dense connective tissue bands that attach bone to bone across joints. They limit excessive movement and provide stability while still permitting normal joint motion. Option b is incorrect because tendons connect muscle to bone, transferring contractile force to the skeleton; they do not connect two bones to each other across a joint. Option c is incorrect because cartilage cushions joint surfaces and forms structures like the nose and ears; it is not the bone-to-bone connecting tissue across joints. Option d is incorrect because fascia is connective tissue that wraps muscles and organs, providing support and separation; it does not specifically link bone to bone.