Key Concepts in Biology and Chemistry
I. Human Biology
A. Blood and Circulation
Universal Blood Donor: Individuals with Type O blood are known as
universal donors.
Universal Blood Acceptor: Individuals with Type AB blood are universal
acceptors.
Low Blood Oxygen Levels: Blood oxygen levels are most likely low when
blood fills the right atrium. This is because deoxygenated blood from the
body returns to the heart via the right atrium.
B. Cellular Communication
Intracellular Chemical Signals: An intracellular chemical signal produced
in the cell membrane travels to another part of the same cell to elicit a
response.
C. Digestive System
Mastication: After food is masticated (chewed) in the oral cavity, it
proceeds to the pharynx.
Nutrient Diffusion: The majority of nutrient diffusion into the bloodstream
occurs in the small intestine due to its large surface area and specialized
structures.
D. Immune System
Pathogens: An invading microorganism or agent that triggers an immune
response is known as a pathogen.
E. Musculoskeletal System
Skeletal Muscle: Skeletal muscle tissue is found attached to bones,
enabling movement.
, F. Nervous System
Sensory Perception: Smelling something sweet is initially perceived as
sensory information by the nervous system.
Sympathetic Nervous System: The sympathetic part of the nervous system
is stimulated during a "fight or flight" response, leading to effects like
sweaty palms and a racing heart.
G. Tissues
Connective Tissue: This type of tissue includes cells of the immune system
and blood.
H. Homeostasis
Definition: Homeostasis is best described as a relatively constant
environment within the body, essential for proper physiological
functioning.
I. Reproductive System
Fertilization: The fusion of a sperm and an ovum (fertilization) results in a
zygote.
Male Reproductive Structures: The penis and epididymis are included in
the male reproductive system.
J. Respiratory System
Air Conduction: The trachea plays a crucial role in air conduction to the
lungs.
K. Hematopoiesis
System Association: The skeletal system is most closely associated with the
cardiovascular system when hematopoiesis (blood cell formation) occurs
in the bone marrow.
L. Urinary System
Final Urine Passage: The final structure through which urine travels to exit
the body is the urethra.