Human Physiology Final Study Guide

Which of the following is not an example of a negative homeostatic mechanism in the human body?

Retaining fluid leading to retaining more fluid

Which of the following must the human body obtain from the environment in order to survive?

Water

Positive feedback mechanisms usually produce

unstable conditions

The difference in hydrogen ion concentration between solutions with pH 4 and pH 5 is

Tenfold

A person has alkalosis if the blood pH

 

rises above 7.5

Which of the following is characteristic of carbohydrates?

• they contain C, H, O with twice as many hydrogen as oxygen atoms

• They provide much of the energy that the cell requires

• They all include sugars and starches

All of the above

DNA

 

stores genetic information, including instructions for enzymes that synthesize fats and carbohydrates

What does not influence the rate of diffusion?

 

The amount of energy available for transport molecules

If the concentration of glucose in the water outside of a cell is higher than the concentration inside,

 

water will leave the cell by osmosis

Homeostasis is the 

 

tendency of the body to maintain a stable internal environment

What transport processes does not require expenditure of cellular energy?

 

Facilitated diffusion

Living organisms use oxygen to

 

release energy stored in the molecules of food

Maintaining a stable internal environment typically requires

 

negative feedback mechanisms

A blood clot stimulating further clotting is an example of

 

a positive feedback mechanism

Homeostasis exists if concentrations of water, nutrients, and oxygen in the body and heat and pressure

 

remain within certain limited ranges

Electrolytes that release hydrogen ions in water are

acids

The pH scale measures the

 

concentration of hydrogen ions in solution

Lipids

• are insoluble in water

• include phospholipids, cholesterol, and fats

• contain C, H, and O but with proportionately less oxygen than in carbohydrates

Which of the following is not organic?

• sodium chloride

• lipids

• nucleic acids

• enzymes

Sodium chloride

The parts of a protein that change when it denatures are

the secondary and tertiary strcutures

In phenylketonuria, an individual cannot break down the amino acid phenylalanine. Molecules that include phenylalanine build up in the blood, which causes intellectual disability and other symptoms. This inherited disease can be controlled by following a diet that is very low in

protein

What characteristic do simple diffusion and facilitated diffusion share?

 

Both move a substance rom a region of higher concentration to one of lower concentration without cellular energy

If a red blood cell is placed in a hypotonic solution

 

the cell will swell and may eventually burst

The relationship of osmotic pressure and the number of solute particles in a solution is the 

 

greater the number of solute particles, the greater the osmotic pressure

"Metabolism" refers to

 

all of the chemical reactions in a cell.

The liver

 

forms glucose from noncarbohydrates.

Receptor-mediated endocytosis removes _______ molecules from plasma, delivering cholesterol to the tissues.

LDL

Activities of the digestive system generally increase when it is stimulated by

 

parasympathetic impulses.

One reason protein synthesis is important is that

 

enzymes are proteins and enzymes are essential to metabolism.

When a sucrose molecule is decomposed to yield a glucose molecule and a fructose molecule,

 

a water molecule is used.

An important mechanism that controls metabolic pathways under physiological conditions is

 

negative feedback.

Matthew takes a drug that inhibits the production of HCl in the stomach to ease the symptoms of a gastric ulcer. If he takes it for a long time, digestion of which nutrient would be affected the most

Proteins

Pancreatic digestive secretions are regulated by

cholecystokinin

Gastrin, which stomach cells secrete,

 

increases secretion by the gastric glands.

Inhibition of which hormone may help in weight loss?

Ghrelin

A negative nitrogen balance results from a net loss of

 

amino acids.

Carbohydrates, proteins, and fats are

macronutrients

ATP is important to cellular processes because it

 

provides energy for cellular work when the terminal, high-energy bond is broken.

BMR

 

rises from birth to age five, then declines, then peaks in adolescence, then drops during adulthood.

Lipids include

fats, oils, and cholesterol

What substance increases in abundance during cellular respiration?

ATP

Vanessa takes many vitamin supplements, claiming that they give her energy. She is mistaken, because cells preferentially use _______ for energy.

carbohydrates

The functions of saliva include

 

moistening, binding, and dissolving food particles; beginning chemical digestion of carbohydrates; and cleansing the teeth and mouth.

Factors that affect BMR are

body size, body temperature, and the level of endocrine activity

A molecule that is a storage form of carbohydrate is

glycogen

________ provides short-term energy after cellular glucose supplies are depleted.

Glycogen

After eating, _________ signals the hypothalamus to suppress appetite.

leptin

Secretion of cholecystokinin from the intestinal wall is stimulated by

 

protein and fat in the small intestine.

Which of the following is the correct sequence for the digestion and absorption of lipids? 1. Formation of chylomicrons 2. Emulsification by bile 3. Dissolved in the epithelial cell membrane 4. Hydrolysis by pancreatic lipase 5. Movement into lacteal ducts

 

2, 4, 3, 1, 5

Skin cells play an important role in producing

 

vitamin D

Functions of bones

• to protect certain internal organs

• to provide a source for red and white blood cells

• to store inorganic salts

Oxygen debt in muscles may develop because of

 

the inability of respiratory and circulatory systems to supply enough oxygen to skeletal muscles when used strenuously for a minute or two.

Creatine phosphate

 

supplies energy for the synthesis of ATP.

Cardiac muscle

• contracts as a syncytium

• excites itself

• is only in the heart

Lists the steps of fracture repair in sequence?

 

A hematoma forms, granulation tissue and fibrocartilage develop, osteoclasts and phagocytes clear away debris, bony callus forms.

The functions of skin include

• acting as a protective covering

• housing sensory receptors

• regulating body temperature

Steps in endochondral bone formation

• hyaline cartilage develops into the shape of future bone

• periosteum forms from connective tissue outside the developing bone

• osteoblasts deposit osseous tissue in place of disintegrating cartilage

Skeletal muscles help maintain body temperature in that

 

the more active they are, the more heat is released.

At a neuromuscular junction

 

neurotransmitters are released.

A burn affecting only the epidermis is a

 

superficial partial-thickness burn.

After a severe burn, new skin may grow outwards from the hair follicles. New growth begins here because

 

a hair follicle contains stem cells in the bulb region.

Transverse tubules and sarcoplasmic reticulum are well developed in

 

skeletal and cardiac muscle fibers.

What is the most abundant form in which calcium is found in the inorganic matrix of the bone?

Hydroxyapatite

Activities such as distance swimming and distance running are most likely to stimulate development of

 

slow fatigue-resistant fibers.

A bone lengthens as a result of

increased activity within the epiphyseal plate

Binding sites on the surface of actin allow the formation of cross-bridges with molecules of

myosin

The thyroid hormone thyroxine ______.

 

stimulates replacement of cartilage with bone in the epiphyseal plate

What is a normal response to excessive loss of body heat in a cold environment?

 

Dermal blood vessels constrict.

Smooth muscle lacks

 

transverse tubules and striations

Sweat cools the body by

evaporation

Osteoclasts are

 

cells that break down bone matrix.

When ATP levels are low, the relationship between ATP and creatine phosphate is that

 

creatine phosphate supplies energy to regenerate ATP from ADP and phosphate.

Athletes usually experience muscle fatigue less quickly than nonathletes because they

 

produce less lactic acid.

Steps of muscle fiber contraction

Step 1

The impulse arrives at the synapse and travels through the transverse tubules.

Step 2

The muscle impulse reaches the sarcoplasmic reticulum and calcium is released.

Step 3

Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites.

Step 4

Myosin heads bind to exposed active sites on actin, forming cross-bridges.

Step 5

Thin filaments are pulled over the thick filaments.

Step 6

The muscle fiber shortens and contracts.

The nervous system

• detects changes in the internal or extend environment

• controls movement of muscles

• integrates information from several sources and uses it to determine an appropriate response

Sensory receptors

• monitor light

• monitor sound

• detect changes in and outside the body

Three general functions of the nervous system are

 

integrative, motor, and sensory.

Presynaptic neurons release neurotransmitters by ______________.

exocytosis

When an action potential passes over the surface of a synaptic knob, the contents of the vesicles are released in response to the presence of

 

calcium ions.

If a neuron receives a series of stimuli whose effect is excitatory but subthreshold, the neuron is more excitable to incoming stimulation than before and is said to be

facilitated

Sensory impulses are stimulated at receptors by

 

local changes in their cell membrane potentials.

Transmitting an impulse from one neuron to another involves a(n)

 

impulse stimulating a presynaptic axon to release a neurotransmitter into a synaptic cleft

Action potentials are related to impulses conducted along an axon in that

 

propagation of a series of action potentials along a nerve cell fiber constitutes an impulse.

A stimulus great enough to change the membrane potential and propagate an action potential is said to have reached _________.

threshold

When a nerve fiber is polarized, the concentration(s) of

 

Na+ is higher on the outside of the membrane and K+ is higher on the inside.

Saltatory conduction

 

is faster than conduction on an unmyelinated fiber.

If a resting potential becomes more negative, the membrane is

hyperpolarized

A nerve cell membrane becomes depolarized as a result of

 

some ion channels being opened while others are closed.

An action potential is triggered if

 

EPSPs overpower IPSPs.

What is the correct sequence of events along an axon that follows a membrane reaching threshold potential?

Step 1

Sodium channels open and sodium ions diffuse inward.

Step 2 

The membrane depolarizes.

Step 3

Potassium channels open and potassium ions diffuse outward.

Step 4

The membrane repolarizes.

In reuptake

 

a neurotransmitter that has already been released into the synaptic cleft is taken back into the synaptic knob of the presynaptic neuron or into nearby neuroglia or neurons.

Olfactory receptors, which provide the sense of smell are

chemoreceptors

Marjorie takes an anti-anxiety drug so that she can sleep better and remain calm enough to study effectively. She begins by taking 25 milligrams every evening, but within a month this dose is no longer helping, so she takes two pills. After another month this dosage is no longer effective. This is happening because

 

the number of receptors to which the drug binds on neurons has declined.

List the parts of a reflex arc in the correct sequence?

 

Receptor, sensory neuron, interneuron, motor neuron, effector

The somatic nervous system consists of nerve fibers that connect the CNS to the ______, whereas the autonomic nervous system consists of fibers that connect the ______.

 

skin and skeletal muscles; CNS to the visceral organs

Baroreceptors are stimulated by

blood pressure changes

Pain receptors are stimulated by

damage to tissue

Thermoreceptors are stimulated by

temperature changes

Bob witnesses an auto accident and impulses from the ___________ division of the autonomic nervous system increase his heart rate.

sympathetic

Adrenergic fibers

 

Sympathetic postganglionic fibers