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Honors Biology
Unit 11 - Body Tissues, regulating internal environment, (excretion) and
Digestion/Nutrition
Chapter 21:
1. List the structural hierarchy in a human, and explain the difference between the
study of "anatomy" and "physiology."
Anatomy - study of the structure of an organism and its parts
Physiology - study of the function of these structures
Cellular level
Tissue level
Organ level
Organ system level
Organism level
2. Define "tissue" and describe the following types of tissue:
Tissue - a collection of many structurally similar cells that act to perform a specific
function (Ex: cardiac muscle tissue)
1. Epithelial -covers surface of body, lines organs and cavities. Sheets of tightly packed
cells riveted together. Ex: outer layer of skin, linings of heart, blood vessels digestive
tract, respiratory tract, genitourinary tract.
2a. Loose connective - most widespread, binds epithelia to underlying tissues, holds
organs in place. Loose weave of protein fibers (ex: collagen), very strong, has elastic
fibers. (Ex: under the skin)
b. Adipose connective - stores fat in closely packed cells in sparse matrix of fibers. Fats
stores energy, insulates body. Contains large globule of fat; cell swells when fat is
stored, shrinks when fat is stored, shrinks when fat is used for energy.
c. Blood - red and white blood cells are suspended in liquid matrix called plasma. Blood
functions in transporting substances through body, and in immunity.
d. Fibrous connective tissue - has dense matrix of collagen, forms tendons (attach
muscle to bone) anSkeletal muscle - attached to bones by tendons. Voluntary, striated.
Fixed number. Weight lifting only enlarges those present.
3a. Cardiac muscle - in heart, striated, branched, involuntary.
b. Smooth muscle - in walls of organs, blood vessels. Is involuntary. Contracts
slowly, but remains contracted longer than skeletal. No striations.
4. Nervous Tissue - relays information from one body part to another. Neurons (nerve
cell) transmit electrical signals
3. Give an overview of the 11 major organ systems in a human:
Integument (skin): Protection from the elements
Skeletal: Provides body support for locomotion and protects internal organs
Respiratory: Allows for gas exchange (waste CO2 and takes in O2 - necessary for all
cellular metabolism)
Reproductive: Produces offspring
Nervous: Senses changes in the environment and enables the body to respond through
movement or some other function
Muscular: Enables movement
Immune: Defends body from pathogens and disease causing agents
Excretory: Enables the body to expel waste materials
Endocrine: Produces hormones which interact with other systems of the body to allow
for other bodily functions
Digestive: Breaks down food into its components and absorbs nutrients necessary for
bodily activity
Circulatory: Transports nutrients and oxygen to all the cells in the body and transports
waste from the cells to excretory organs
4. Explain how the exchange between the external and internal environments in complex
animals is indirect, as compared with lower animals who's exchange is direct.
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We have an “Open System” = exchange chemicals and energy with surroundings
continuously
Ex: eat, breathe, defecate, urinate, sweat, radiate heat
In = nutrients and O2
Out = waste and CO2
Cells are bathed in water - substances are dissolved in it
We are complex animals- have extensively folded/branched internal surfaces for more
surface area
Ex: alveoli in lungs
Ex: villi in small intestine
We exchange indirectly via our circulatory system.
5. Explain how the body regulates its internal environment. Utilize the following
concepts:
1. Homeostasis = steady state - internal body (interstitial fluid) maintains constant
conditions even when external environment changes. Ex: body temperature
2. Negative feedback - the results of some process inhibit that very same process
Ex: thermostat-Increase heat, heat shuts down.
Ex: FSH-high levels of FSH shuts down FSH. “on and off switch”
3. Positive feedback - the results of a process intensifies that same process
Ex: labor - muscles contract uterus, uterus stimulates release of more hormones, more
contractions.
“On and on more switch”
3. Thermoregulation - the maintenance of internal body temperature close to a set point.
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Endotherms - derive heat from metabolism
Heat loss-is helped regulated by hair, fur, fat, migration, huddling, clothing, sweating,
panting.
Humans-blood vessels constrict near surface when cold, muscles shiver, metabolic
rate increases
4. Osmoregulation - control of the gain or loss of water and dissolved solutes
Gain water from eating or drinking
Lose water through urinating, defecating, breathing, perspiring
Ex: Kidneys help us regulate this
6. Describe the major functions (physiology) of the excretory system, and its anatomy
7. Define the four stages of food processing:
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1. Ingestion - eating
2. Absorption - uptake of the small molecules by cells lining the digestive tract Ex:
from small intestine to bloodstream
3. Elimination - disposal of undigested materials left over from food we eat
4. Digestion - breakdown of food to small nutrient molecules Ex: glucose, amino
acids, fatty acids & glycerol
a. Mechanical - physical processes such as chewing, exposes food to chemicals
b. Chemical - breakdown of food by enzymes (hydrolysis)
8. Explain the role of the following in human nutritional requirements:
Calories - amount of energy required to raise the temperature of a gram of water 1 degree
C.
Metabolic Rate - the rate of energy consumption by the body = BMR + additional
energy consumption above BMR)
Basal metabolic rate (BMR) = amount of energy just to maintain basic body functions
8 essential amino acids:
phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine, and lysine
Malnutrition -a deficiency of one or more of the essential nutrients.
Cause: Inadequate intake or medical problems. Most = protein deficiency. Victims
likely to be retarded in mental and physical development.
Ex: Kwashiorkor - (see left) inadequate protein intake. Deficiency in blood proteins
causes swelling of the belly and limbs.
Undernutrition - body breaks down its own molecules, muscles, brain proteins.
Obesity - inappropriately high ratio of weight to height. 1/4 of Americans