Compact, complex animals have internal exchange surfaces that are extensively branched or folded, providing a large
In the digestive system nutrients are
absorbed across the many fingerlike projections of the lining of the intestine
in the respiratory system
oxygen and carbon dioxide are exchanged across the epithelial linings of sacs at the tips of tiny air tubes
in the urinary system
wastes are removed from the blood across the epithelial linings of excretory tubes.
The circulatory system
transports materials between the exchange surfaces of the other organ systems and body cells
Body cells are bathed in interstitial fluid, and exchange
body cells and the blood takes place through this fluid
compact, complex animals have specialized internal
exchange surfaces that provide a large surface area
Most of the control mechanisms that maintain an internal steady state are based on
negative feedback in which a change in variable triggers mechanisms that reverse that change
Which of the following is an organizational level that encompasses many organ systems working together?
Which of the following is the primary function of the nervous tissue?
rapid communication of signals
What type of epithelium would you expect to find covering a surface subject to physical forces?
What type of epithelial tissue, found in the intestines, absorbs nutrients?
simple columnar epithelium
Which of these tissues, found in the lungs, permits gas exchange by diffusion?
simple squamous epithelium
The type of epithelium that lines the inside of your cheeks (within your mouth) is _____.
stratified squamous epithelium
How does connective tissue differ from the other three major tissue types?
Connective tissue often consists of relatively few cells embedded in an extracellular matrix.
Which of these describes loose connective tissue?
It is a loose weave of fibers that functions as a packing material.
What type of muscle is responsible for contractions of the digestive tract and arteries?
Skeletal muscles are attached to bones by _____, which are made of _____.
tendons ... fibrous connective tissue
Which of the following tissues is responsible for food absorption in the small intestines?
Severe burn victims often receive artificial skin grafts. Why?
Skin normally provides a protective barrier between the body and infectious microorganisms in the environment.
A physician wishes to assess the metabolic activity of a patient's brain. Which imaging technique should she choose?
In addition to the integrity of the integumentary system, what other component of the skin protects against bacterial infection?
If blood sugar is under homeostatic control using negative feedback, what will happen if blood sugar levels drop between meals?
Blood sugar will begin to rise until it reaches an appropriate value.
Which of the following is a correct match of cell type with structure
muscle cell ... has proteins that slide back and forth
Which of the following options lists the structural elements of organisms in the correct order, from smallest to largest?
cells, tissues, organs, organ systems, organisms
The heart pumps blood through blood vessels to reach all areas of the body. Together, the heart and blood vessels form a(n) __________.
What aspect of a bird's wings would be most interesting to a physiologist?
role of feather barbs in flight
In terms of hierarchy of organization, organs fall between _____ and _____.
tissues ... organ systems
is a group of similar cells which have a particular structure and work together to carry out a specific job.
Simple squamous epithelium
is only one cell layer thick, permitting gases to diffuse between the blood and the lungs.
Simple cuboidal epithelium
is also one cell layer thick, forming tiny tubules that allow the blood to be easily filtered in the kidneys.
Simple columnar epithelium
has a single layer of elongated cells that are specialized for absorption of nutrients in the intestine.
Stratified squamous epithelium
has several layers of cells. It is located wherever the body needs protection from abrasion, like inside your esophagus or the surface of your skin.
Pseudostratified squamous epithelium
secretes mucus to trap pathogens and debris before they can enter your lungs, and has cilia to sweep them upward and out of your respiratory tract.
consisting of a web of fibers embedded in either a liquid, jelly, or solid, depending on the type of connective tissue.
Loose connective tissue,
the most common type in the human body, binds skin to underlying muscles and holds internal organs and tissues in place. has both tough collagen fibers and stretchy elastic fibers
Fibrous connective tissue
is made of long tough parallel fibers that resist stretching—useful for tendons and ligaments!
is specialized to store fat. It cushions internal organs, provides insulation, and acts as the body's energy reserve
is smooth and slippery. It covers the ends of bones, allowing them to slide past each other when you move your joints.
provides strength and support. It also acts as a calcium and phosphorus "bank," storing these minerals until the body "withdraws" them as needed.
is a liquid connective tissue that transports substances like oxygen and nutrients to the cells that need them, and carries away carbon dioxide and other wastes.
is attached to bones. It is made of long parallel cylindrical cells. It is voluntary—that is, you can choose to contract it or not.
is made of branched, interconnected cells that can communicate with each other. It is involuntary—you can't consciously control its contraction.
is made of spindle-shaped cells that also communicate with each other. It also contracts involuntarily, to move substances through the body—like in the intestine.
tissue that receives messages from the body's external and internal environment, analyzes the data, and directs the response
When a tissue is injured, the body replaces the damaged tissue by mitosis (except in types like cartilage and cardiac muscle, which do not regenerate).
Transports oxygen and nutrients to the cells.
Transports carbon dioxide and wastes away from the cells for excretion
Exchanges gases with the environment.
Supplies blood with oxygen and disposes of carbon dioxide.
Protects against mechanical injury, infection, excessive heat or cold, and drying out.
Supports the body.
Protects certain internal organs, such as the brain and lungs.
Provides the framework for muscles to produce movement.
Removes nitrogen-containing waste products from the blood.
Regulates the chemical makeup and water balance of the blood.
Ingests and breaks down food into smaller chemical units to be used as fuel for cellular respiration.
Eliminates undigested material.
Secretes hormones that regulate body activities such as digestion, metabolism, growth, reproduction, heart rate, and water balance.
Lymphatic and Immune Systems
Returns excess body fluid to the circulatory system.
Defends the body against infections and cancer.
Coordinates body activities by detecting stimuli, integrating information, and directing the body's responses.
Produce gametes and sex hormones.
Female system includes organs to support a developing embryo and glands for producing milk.
CT (computed tomography)
Useful as a diagnostic tool- for example, for detecting brain hemorrhage, tumors, heart defects, or blocked blood vessels.
MRI (magnetic resonance imaging)
Useful for observing soft tissue, especially if surrounded by bone.
PET (positron-emission tomography)
PET scans can be used to study diseases affecting the brain such as stroke, Alzheimer's, and epilepsy.
Despite large fluctuations in external environment (for example, temperature extremes), homeostatic mechanisms regulate an animal's internal environment, resulting in much smaller fluctuations.