Chapter 35 Human Body Systems

Impulses

The messages carried by the Nervous System are electrical signals

The choroid is

The middle layer of eye that is rich in blood vessels

The sclera is

The outer layer of eye that maintains its shape Serves as the point of attachment for muscles that move the eye

The retina is

The inner layer of eye that contains photoreceptors

Cell Body

The largest part of a typical neuron It contains the nucleus

Each half of the Cerebrum deals with the opposite side of the body

The left half of the cerebrum controls the right side of the body The right half of the cerebrum controls the left side of the body

How is the body organized?

The levels of organization in a multicellular organism include: • cells • tissues • organs • organ systems

Neurons

Cells that transmit impulses

The human nervous system has two major divisions

Central Nervous System and Peripheral Nervous System

Dendrites

Extend from the cell body and carry impulses from the environment toward the cell body

Nervous Tissue

Transmits nerve impulses throughout the body

Neurotransmitters

Chemicals used by a neuron to transmit an impulse across a synaspe to another cell

These sense organs include

1. Eyes (Sight) 2. Ears (Hearing) 3. Nose (Smell) 4. Mouth (Taste) 5. Skin (Touch)

What are the five types of sensory receptors?

1. Pain Receptors 2. Thermoreceptors 3. Mechanoreceptors 4. Chemoreceptors 5. Photoreceptors

The eye has three layers

1. the retina 2. the choroid 3. the sclera

How many organ systems are there in the body?

11

Cells

A cell is the basic unit of structure and function in living things. Individual cells in multicellular organisms are specialized.

Fetal alcohol syndrome (FAS)

A group of birth defects caused by the effects of alcohol on the fetus.

What is an organ?

A group of different types of tissues that work together to perform a single function

Organ Systems

A group of organs that perform closely related functions

Cerebellum

A large structure of the hindbrain that controls fine motor skills. Coordinates and balances the actions of the muscle

Cerebrospinal Fluid

Acts as a shock absorber that protects the central nervous system

What are the structures of the Respiratory System?

Nose, Pharynx, Larynx, Trachea, Bronchi, Bronchioles, and Lungs

A reflex is

A quick, automatic response to a stimulus

Sensory Receptors

A specialized neuron that detects a particular category of physical events

Threshold Stimulus

A stimulus must be of adequate strength to cause a neuron to transmit an impulse. The minimum level of a stimulus that is required to activate a neuron

What is the effect of alcohol on the body?

Alcohol is a depressant that slows down the rate at which the central nervous system functions.

Muscle Tissue

Along with bones, enables the body to move.

How is a nerve impulse transmitted?

An impulse begins when a neuron is stimulated by another neuron or by the environment.

Tissues

An integrated group of cells with a common structure, function, or both.

Drug

Any substance, other than food, that changes the structure or function of the body

Cerebrum

Area of the brain responsible for all voluntary activities of the body Site of intelligence, learning, and judgment

Lens

Behind the iris Muscles attached to the lens change its shape to adjust focus to see near or distant objects

What are the structures of the Skeletal System?

Bones, Cartilage, Ligaments, and Tendons

What are the structures of the Nervous System?

Brain, spinal cord, sensory receptors, nerves

What is the function of the Circulatory System?

Brings oxygen, nutrients, and hormones to cells Fight infection Removes cell wastes Helps to regulate body temperature

Motor Neurons

Carry impulses from the brain and spinal cord to muscles and glands

Sensory Neurons

Carry impulses from the sense organs to the spinal cord and brain

Cocaine

Causes the sudden release in the brain of a neurotransmitter called dopamine.

Interneurons

Connects sensory and motor neurons and carry impulses between them

Brain Stem

Connects the brain and spinal cord

What are the functions of the Nervous System?

Controls and Coordinates functions throughout the body and responds to internal and external stimuli

What is the function of the Endocrine System?

Controls growth, development and metabolism Maintains homeostasis

Hypothalamus

Controls recognition and analysis of hunger, thirst, fatigue, anger, and body temperature

What is the function of the Digestive System?

Converts food into simpler molecules that can be used by the cells of the body Absorbs food Eliminates wastes

Hearing

Ears can distinguish both the pitch and loudness of vibrations

What is the function of the Excretory System?

Eliminates wastes products from the body in ways that maintain homeostasis

What are the four basic types of tissues in the human body?

Epithelial, Connective, Nervous, and Muscle

Photoreceptors

Found in eyes Sensitive to light

Mechanoreceptors

Found in the skin, skeletal muscles, and inner ears Sensitive to touch, pressure, stretching of muscles, sound, and motion

The human ear has two sensory functions

Hearing & Balance

What are the structures of the Circulatory System?

Heart, Blood, Blood Vessels

What is the function of the Lymphatic/Immune System?

Helps protect the body from disease Collects fluids lost from blood vessels and returns the fluid to the circulatory system

What are the structures of the Endocrine System?

Hypothalamus, Pituitary, Thyroid, Parathyroid, Adrenals, Ovaries (in females) and Testes (in males)

A reflex arc

Includes a sensory receptor, sensory neuron, motor neuron, and effector that are involved in a quick response to a stimulus.

Epithelial Tissue

Includes glands and tissues that cover interior and exterior body surfaces

Stimulants

Increase heart rate, blood pressure, and breathing rate. Increases the release of neurotransmitters at some synapses in the brain.

Chemoreceptors

Located in nose and taste buds Sensitive to chemicals in the external environment

Thermoreceptors

Located in the skin, body core, and hypothalamus Detect variations in temperature

Pain Receptors

Located throughout the body except in the brain. They respond to chemicals released by damaged cells Pain usually indicates danger, injury, or disease

Axon

Long fiber that carries impulses away from the cell body of a neuron

Opiates

Mimic endorphins which normally help to overcome sensations of pain.

What are the structures of the Digestive System?

Mouth, Pharynx, Esophagus, Stomach, Small and Large Intestines, Rectum

Feedback Inhibition

Process in which a stimulus produces a response that opposes the original stimulus

What is the function of the Reproductive System?

Produces reproductive cells In females, nurtures and protects developing embryo

What is the function of the Respiratory System?

Provides oxygen needed for cellular respiration and removes excess carbon dioxide from the body

Connective Tissue

Provides support for the body and connects all of its parts

Thalamus

Recieves messages from sensory receptors throughout the body and relays the information to the proper region of the cerebrum

What is the function of the Nervous System?

Recognizes and coordinates the body's response to changes in its internal and external environments

What are the functions of the Central Nervous System?

Relays messages, Processes information and Analyzes information

Cones

Respond to light of different colors, producing color vision

Rods

Sensitive to light, but not color

What is the function of the Integumentary System?

Serves as a barrier against infection and injury Helps regulate body temperature Provides protection against ultraviolet radiation from the sun

What are the structures of the Muscular System?

Skeletal Muscle, Smooth Muscle, Cardiac Muscle

What are the structures of the Integumentary System?

Skin, Hair, Nails, Sweat and Oil Glands

What are the structures of Excretory System?

Skin, Lungs, Kidneys, Uterus, Urinary bladder, and Urethra

Depressants

Slow down heart rate and breathing rate, lower blood pressure, relax muscles, and relieve tension.

Drugs differ in the ways in which they affect the body

Some kill bacteria and are useful in treating disease. Others affect a particular system of the body. Others cause changes to the brain and synapses.

What are the different classes of drugs that directly affect the central nervous system?

Stimulants & Depressants

Specialized Cells

Suited to perform a particular function

What is the function of the Skeletal System?

Supports the body Protects internal organs Allows movement Stores mineral reserves Provides a site for blood cell formation

What are the structures of the Reproductive System?

Testes, Epididymis, Vas Deferens, Urethra, and Penis (in males) Ovaries, Fallopian Tubes, Uterus, and Vagina (in females)

Homeostasis

The process by which organisms keep internal conditions relatively constant despite changes in external environments

Taste Buds

The sense organs that detect taste

What are the two divisions of the peripheral system?

The sensory division of the peripheral nervous system transmits impulses from sense organs to the central nervous system.

Myelin Sheath

There are gaps in the myelin sheath, called nodes, where the membrane is exposed. Impulses jump from one node to the next.

Meninges

Three layers of connective tissue in which the brain and spinal cord are wrapped

Addiction

Uncontrollable dependence on a drug

Cochlea

Vibrations of the oval window create pressure waves in the fluid-filled cochlea of the inner ear

What are the structures of the Lymphatic/ Immune Systems?

White blood cells, Thymus, Spleen, Lymph Nodes, Lymph vessels

Semicircular Canals

Within the inner ear, just above the cochlea are three semicircular canals.

What is the function of the Muscle System?

Works with skeletal muscle to produce voluntary movement Helps to circulate blood and move food through the digestive system