Bio 168 Test Exam Questions Correct Answers 2025 New Update

Bio 168 Test Exam Questions Correct Answers 2025 New Update The major tissue types and their functions - Answers - epithelial tissue covers body surfaces; connective tissue supports other tissues structurally; nervous tissue is responsible for rapid long-distance signalling, coordination, and "thinking"; muscle tissue is specialized for movement by means of cellular contraction The major differences between tissues - Answers - ***SEE ATTACHED SHEETS*** The cell types and proteins that make tissues - Answers - collagen is the most abundant protein; actin, myosin, The different layers of the skin and the associated terms - Answers - The skin has three layers—the epidermis, dermis, and fat layer (also called the subcutaneous layer); The deepest layer of the epidermis, the stratum basale, is a single layer of cells resting on a basement membrane (layer between the dermis and epidermis), they divide continuously. As new cells form, older ones are pushed toward the skin surface; The next layer, the stratum spinosum, consists of spiny prickle cells that interlock to support the skin; The stratum granulosum, the thin middle layer, initiates keratinization (production of keratin). This process starts the death of epithelial cells (the cell type that makes up skin); The stratum lucidum protects against sun ultraviolet-ray damage. This thick layer appears only in frequently used areas such as palms of the hands and soles of the feet; The stratum corneum, the fifth, outermost layer is thick with rows of dead cells. These cells contain soft keratin, which keeps the skin elastic and protects underlying cells from drying out. Types of burns and how they are classified, including the rule of nines - Answers - An adult who has been burned, the percent of the body involved can be calculated as follows: Head = 9% Chest (front) = 9% Abdomen (front) = 9% Upper/mid/low back and buttocks = 18% Each arm = 9% (front = 4.5%, back = 4.5%) Groin = 1% Each leg = 18% total (front = 9%, back = 9%) The general steps in the inflammatory response in skin - Answers - line of defense triggered by penetration of the skin or mucous membranes, in which small blood vessels in the vicinity of an injury dilate and become leakier, enhancing the inflitration of leukocytes (white blood cells) The parts of a long bone, the cells that are found and where, and the protein in bone - Answers - One of the types of tissue that makes up bone is the mineralized osseous tissue, also called bone tissue, that gives it rigidity and a coral-like three-dimensional internal structure. Other types of tissue found in bones include marrow, endosteum, periosteum, nerves, blood vessels and cartilage; Components of bone: * The organic matrix is compsed primarily of the protein collagen which provides flexibility. 10% of adult bone mass is collagen. This is discussed further in the section on collagen and bone matrix * The mineral component is composed of hydroxyapatite, which is an insoluble salt of calcium and phosphorus. About 65% of adult bone mass is hydroxyapatite. * Bone also contains small amounts of magnesium, sodium, and bicarbonate. * Water comprises approximately 25% of adult bone mass. Bone repair - Answers - 1. A bone fracture hematoma (blood clot) occurs 2. A fibrocartilaginous (soft) callus forms 3. A bony (hard) callus replaces the soft callus 4. The bone is remodeled The major differences between the joint types, especially know the structure of a synovial joint - Answers - ... Movements of joints - Answers - flexion, extension, abduction, adduction, and circumduction The major imbalances affecting bones and joints (arthritis, spine curvatures, etc) - Answers - ... The macroscopic and microscopic structure of muscle - Answers - ***SEE ATTACHED SHEET*** What are the structure and function of myosin and actin - Answers - two proteins, myosin and actin work together to help the muscle cells relax and contract. The two proteins need each other and together they are called actomyosin. ***SEE ATTACHED SHEETS*** the importance of calcium (where it is stored and what it does) - Answers - When a nerve impulse (action potential) arrives at a synapse, (Ca2+) calcium ions are absorbed into the neuron. they stimulate the synaptic vesicles, containing neurotransmitter, to fuse with the cell membrane and release the neurotransmitter into the synapse. The general sequence of events in a muscle contraction (there are 3 questions related to the order of events - for example, ACh binding to receptors opens chemically-gated sodium channels which is followed by opening of voltage-gated sodium channels) - Answers - 1. Action potentials in a somatic motor neuron cause the release of acetylcholine neurotransmitter at the myoneural junction (one myoneural junction per myofiber). 2. Acetylcholine, through its interaction with receptors in the muscle cell membrane (sarcolemma), produces action potentials that a reregenerated across the sarcolemma. 3. The membranes of the transverse tubules (T tubules) are continuous with the sarcolemma and conduct action potentials deep into the muscle fiber. 4. Action potentials in the T tubules, acting through a mechanism that is incompletely understood, stimulate the release of (calcium ions) Ca2+ from the terminal cisternae of the sarcoplasmic reticulum. 5. Ca2+ released into the sarcoplasm attaches to troponin, causing a change in its structure. 6. The shape change in troponin causes its attached tropomyosin to shift position in the actin filament, thus exposing binding sites for the myosin cross bridges. 7. Myosin cross bridges, previously activated by the hydrolysis of ATP, attach to actin. 8. Once the previously activated cross bridges attach to actin, they undergo a power stroke and pull the thin filaments over the thick filaments. 9. Attachment of fresh ATP allows the cross bridges to detach from actin and repeat the contraction cycle as long as Ca2+ remains attached to troponin. 10. When action potentials stop being produced, the sarcoplasmic reticulum actively accumulates Ca2+ and tropomyosin returns to its inhibitory position. The cause of rigor mortis - Answers - temporary stiffening of skeletal muscles observed in the period between 4 hours and 48 hours after death. It is due to the leakage of calcium ions from the sarcoplasmic reticulum into the general sarcoplasm which triggers binding of actin and myosin. The leakage occurs because in death there is no further ATP production and the (calcium ions) Ca+2 pump in the sarcoplasmic reticulum membranes cease to function. Abduction - Answers - movement of a limb away from the body Acetylcholine - Answers - neurotransmitter that diffuses across a synapse and produces an impulse in the cell membrane of a muscle (contraction)