HAPS Exam Practice A&P 1

What is homeostasis?

The maintenance of a relatively stable internal environment despite changes inside or outside the body.

What is the difference between homeostasis and equilibrium?

Homeostasis maintains conditions within a narrow range, while equilibrium means conditions are completely balanced with no net change.

What are the three components of a homeostatic control system?

A receptor, a control center, and an effector.

What is the function of a receptor in homeostasis?

To detect changes in the internal or external environment.

What is the function of a control center?

To compare incoming information to a set point and determine an appropriate response.

What is the function of an effector?

To carry out the response that restores homeostasis.

What is negative feedback?

A mechanism that reverses a change and returns the body toward its set point.

What is positive feedback?

A mechanism that amplifies a change until a specific event is completed.

What is an example of positive feedback?

Childbirth, where oxytocin increases uterine contractions until delivery.

What is another example of positive feedback?

Blood clotting, where activated platelets recruit additional platelets until the clot forms.

What is metabolism?

The sum of all chemical reactions occurring within the body.

What is catabolism?

The breakdown of larger molecules into smaller molecules, releasing energy.

What is anabolism?

The synthesis of larger molecules from smaller molecules, requiring energy.

What is ATP?

The primary energy currency of the cell.

Why is ATP important?

It provides energy for cellular work such as muscle contraction, active transport, and protein synthesis.

What is an atom?

The smallest unit of an element that retains its chemical properties.

What are protons?

Positively charged particles located in the nucleus.

What are neutrons?

Uncharged particles located in the nucleus.

What are electrons?

Negatively charged particles found outside the nucleus.

What determines an element's atomic number?

The number of protons.

What is an ion?

An atom that has gained or lost electrons and therefore has a charge.

What is a cation?

A positively charged ion formed by losing electrons.

What is an anion?

A negatively charged ion formed by gaining electrons.

What is a covalent bond?

A bond formed by sharing electrons.

What is an ionic bond?

A bond formed by the attraction between oppositely charged ions.

What is a hydrogen bond?

A weak attraction between a hydrogen atom and another electronegative atom.

Why are hydrogen bonds important?

They help maintain the structure of proteins, DNA, and water.

What makes water a polar molecule?

Its unequal sharing of electrons creates partial positive and negative ends.

Why is water an excellent solvent?

Its polarity allows it to dissolve many ionic and polar substances.

What is pH?

A measure of hydrogen ion concentration in a solution.

What are carbohydrates primarily used for?

Providing quick energy.

What is glucose?

The body's primary fuel molecule.

What are lipids primarily used for?

Long-term energy storage, insulation, and cell membrane structure.

What is the main component of the cell membrane?

A phospholipid bilayer.

What are proteins made of?

Amino acids.

What is the primary function of proteins?

They perform structural, enzymatic, transport, signaling, and contractile roles.

What is an enzyme?

A protein that speeds up chemical reactions without being consumed.

What is the active site of an enzyme?

The region where the substrate binds.

What can affect enzyme activity?

Temperature, pH, substrate concentration, and enzyme concentration.

What are nucleic acids?

DNA and RNA, which store and transmit genetic information.

What is the cell theory?

All living things are made of cells, cells are the basic unit of life, and all cells arise from preexisting cells.

What is the plasma membrane?

A selectively permeable barrier surrounding the cell.

What is selective permeability?

The ability of the membrane to allow some substances to pass while restricting others.

What is diffusion?

The passive movement of molecules from an area of higher concentration to lower concentration.

What is osmosis?

The diffusion of water across a selectively permeable membrane.

What is facilitated diffusion?

Passive transport using membrane transport proteins.

What is active transport?

Movement of substances against their concentration gradient using ATP.

What is the sodium-potassium pump?

An ATP-powered transport protein that moves three sodium ions out of the cell and two potassium ions into the cell.

What is the function of mitochondria?

To produce ATP through cellular respiration.

What is the function of ribosomes?

To synthesize proteins.

What are the four primary tissue types?

Epithelial, connective, muscle, and nervous tissue.

What is the primary function of epithelial tissue?

Protection, secretion, absorption, filtration, and diffusion.

What are the characteristics of epithelial tissue?

Closely packed cells, little extracellular matrix, avascular, and attached to a basement membrane.

What is the basement membrane?

A thin layer that anchors epithelial tissue to the connective tissue beneath it.

What is simple epithelium?

A single layer of cells specialized for absorption, secretion, or diffusion.

What is stratified epithelium?

Multiple layers of cells specialized for protection.

Where is simple squamous epithelium found?

Alveoli of the lungs, capillaries, and blood vessels.

Why is simple squamous epithelium ideal for diffusion?

Its thin, single-cell layer minimizes diffusion distance.

Where is simple cuboidal epithelium commonly found?

Kidney tubules and many glands.

What is the primary function of simple cuboidal epithelium?

Secretion and absorption.

Where is simple columnar epithelium found?

Most of the digestive tract.

What is the function of simple columnar epithelium?

Absorption and secretion of mucus and digestive enzymes.

What is pseudostratified ciliated columnar epithelium?

A single layer of cells that appears multilayered and contains cilia.

Where is pseudostratified ciliated columnar epithelium found?

Most of the upper respiratory tract.

What is the function of cilia in the respiratory tract?

To move mucus and trapped particles toward the pharynx.

Where is stratified squamous epithelium found?

The epidermis, mouth, esophagus, and vagina.

Why is stratified squamous epithelium well suited for protection?

Its multiple layers resist abrasion and injury.

What is transitional epithelium?

Stretchable epithelium found in the urinary bladder, ureters, and proximal urethra.

Why is transitional epithelium important?

It allows urinary organs to expand and recoil without damage.

Which epithelial tissue is most commonly associated with rapid diffusion?

Simple squamous epithelium.

What is the primary function of connective tissue?

Support, protection, binding, storage, and transport.

What three components make up connective tissue?

Cells, fibers, and ground substance.

What are fibroblasts?

Cells that produce connective tissue fibers and ground substance.

What are the three major fiber types in connective tissue?

Collagen, elastic, and reticular fibers.

What is the function of collagen fibers?

Provide strength and resist stretching.

What is the function of elastic fibers?

Allow tissues to stretch and recoil.

What is cartilage?

A flexible connective tissue that provides support and cushioning.

Why does cartilage heal slowly?

It lacks a direct blood supply.

What is the function of bone as connective tissue?

Support, protection, mineral storage, and blood cell production.

Why is blood considered connective tissue?

It has cells suspended in an extracellular matrix called plasma.

What are the three muscle tissue types?

Skeletal, cardiac, and smooth muscle.

Which muscle tissue is voluntary?

Skeletal muscle.

Which muscle tissue is found only in the heart?

Cardiac muscle.

Which muscle tissue is found in hollow organs?

Smooth muscle.

What is the primary function of nervous tissue?

Rapid communication through electrical signals.

What are the major functions of the integumentary system?

Protection, temperature regulation, sensation, vitamin D synthesis, and preventing water loss.

What are the two major layers of the skin?

The epidermis and dermis.

Which skin layer is made of epithelial tissue?

The epidermis.

Which skin layer contains blood vessels?

The dermis.

Why is the epidermis avascular?

It receives nutrients by diffusion from the dermis.

What is keratin?

A tough structural protein that strengthens the epidermis.

Which epidermal layer undergoes continuous mitosis?

The stratum basale.

Which epidermal layer consists primarily of dead, keratinized cells?

The stratum corneum.

Which cells produce melanin?

Melanocytes.

What is the function of melanin?

It helps protect DNA from ultraviolet radiation.

What is the function of sweat glands?

To regulate body temperature through evaporative cooling.

What is the function of sebaceous glands?

To secrete sebum, which lubricates the skin and hair.

Why does sweating cool the body?

Evaporation removes heat from the skin.

Which vitamin is synthesized in the skin?

Vitamin D.

What is the body's first line of defense against pathogens?

The intact skin and mucous membranes.