Biology | Unit IV: Human Body Systems, Microorganisms, and Disease

Cells, tissues, organs, and organ systems

What are the levels of organization?

Epithelial Tissue

Tissue mainly made up of skin; used for protection

Connective Tissue

Tissue that binds epithelial tissue to structures

Nervous tissue

Tissue that sends and receives nerve impulses

Homeostasis

Describes the relatively constant internal conditions that organisms maintain despite changes in the internal and external environments.

**Feedback inhibition**

A process in which a stimulus produces a response that opposes the original stimulus, a generally very stable mechanism of control.

Digestive System

Converts food into small molecules that can be used by the cells of the body for energy.

Excretory System

Includes the skin, lungs, liver, and __**kidneys**__; and excretes metabolic waste from the body.

Ammonia

One of the most toxic waste compounds produced by living things

Skin

Removes excess water, salts, and a small amount of urea in sweat

Lungs

Carbon dioxide, a waste product of cellular respiration, is exhaled by the _____

Liver

Converts dangerous nitrogen-based wastes into urea (less toxic)

Kidneys

Remove excess water, urea, and metabolic wastes from the blood

Circulatory System

Transports oxygen, nutrients, and other substances throughout the body, and it removes wastes from tissues

Right side of heart

Pumps **oxygen-poor blood** through the **pulmonary** artery __from the heart to the lungs__ through **pulmonary circulation**

Left side of heart

Pumps **oxygen-rich blood** through the **aorta** __to the rest of the body__ through **systemic circulation**

Arteries

Large vessels that carry blood from the heart to the tissues of the body

Capillaries

Smallest blood vessels so small that blood cells can pass through in single file; thin walls allow oxygen and nutrients to diffuse into tissues and carbon dioxide in

Veins

Return blood to the heart coming from capillaries

Atria (Upper chambers)

Receive blood

Ventricles (Lower chambers)

Pump blood

It has to pump blood to the rest of the body

Why does the cardiac muscle tissue appear thicker in the lower part of the heart?

Erythrocytes

Red blood cells; transport oxygen; produced in bone marrow

Leukocytes

White blood cells; fight infection

Red

Most blood cells are ___ blood cells.

Lymphatic System

A network of __vessels__, __nodes__, and __organs__ that recycles fluids from tissues and plays a role in nutrient absorption and immunity

Respiratory System

Picks up oxygen from the air we inhale and releases carbon dioxide as we exhale. __In the lungs, gas exchange takes place and oxygen enters the circulatory system.__

Nervous System

Collects information about the __internal__ and __external__ environment, __processes that information__, and __responds to it by sending messages__ in the form of **electrical signals called impulses through neurons**.

Sensory Neurons

Carry impulses from sense organs to CNS

Motor Neurons

Carry impulses from the CNS to muscles and glands

Interneurons

Process information and send commands to other interneurons or motor neurons

Action potential

When a neuron is stimulated beyond a threshold, the resting electrical potential of the membrane changes, inducing a nerve impulse called _____ _______

Central Nervous System

Nervous Sytem: brain and spinal cord

Peripheral Nervous Sytem

Nervous System: rest of body

Skeletal System

Made up of **206 bones** __supports the body__**,** __protects internal organs__, __assists in movement__, __stores minerals__, and is a __site of blood cell formation__

Bone

Living tissue made up of a solid network of cells and protein fibers surrounded by deposits of calcium salts

No

Are bones a solid, dense thing?

Joint

A place where two or more bones meet each other and connective tissues hold bones together while permitting bones to move without damaging each other

Muscular System

Responsible for movement of the body and consists of __three different types of tissue specialized for different functions__: **skeletal, smooth, and cardiac muscle**

They both have stripes

What do cardiac and skeletal muscles have in common?

Sarcomeres

Muscle fiber units called ___________

Actin and Myosin

Sarcomeres contain filaments composed of proteins:

Integumentary System

Made up of __**skin**__ and its related structures (hair, nails, and glands) helps to regulate body temperature, serves as a barrier against infection and injury, removes waste, gathers sensory information, and produces vitamin D

Endocrine System

Contains __**glands**__ that produce and release hormones that travel through the blood and control the actions of cells, tissues, and organs. The system helps regulate mood and metabolism, tissue function, growth and development, and reproductive processes

Disease

An abnormal condition that harms an organism

Louis Pasteur and Robert Koch

Who proposed the Germ Theory of Disease?

Viruses, bacteria, fungi, protists, and other pathogens

Infectious diseases are caused by:

Skin, tears, inflammatory response, and fever

Nonspecific defenses:

B cells and T cells

The main working cells of the immune response

Humoral immunity

Depends on the action of antibodies that circulate in the blood and lymph

Cell-mediated immunity

Defends the body against some viruses, fungi, and single-celled pathogens

Virus

A nonliving particle made of proteins, nucleic acids, and sometimes lipids that reproduce only by infecting living cells

RNA

Do viruses contain more RNA or DNA?

Capsid

Protein coat that surrounds a virus

Lytic and Lysogenic

Types of viral infections:

Parasites

All viruses are _______

Prokaryotes

Small, simple, **unicellular** organisms that lack a nucleus and are classified into two domains: __Bacteria or Archaea;__ Most are single-celled

Bacteria

Usually surrounded by a cell wall; contains peptidoglycan, a polymer of sugars and amino acids

Archaea

Its cell walls lack peptidoglycan, membranes contain a different lipid, and DNA sequence is more similar to eukaryotes than Bacteria

Asexually, binary fission

\
Most prokaryotes reproduce _____ by the process of ____ _____

Conjugation

The exchange of genetic information horizontally; used by Prokaryotes

Emerging disease

A previously unknown disease that appears in a population for the first time or a well-known disease that suddenly becomes harder to control

Protists

The first Eukaryotes; non members of the plant, animal, or fingu kingdoms; most are single-celled

Alternation of generations

Reproduction cycle that combines asexual and sexual forms of reproduction; used by Protists

Food chain

Protists are at the base of the _____ _____

Fungi

Heterotrophic eukaryotes with cell walls that contain **chitin**

Chitin

A polymer made of modified sugars that is also found in the external skeleton of insects

No

Are fungi plants?