Biological Systems and Earth Science Fundamentals

The Nervous System: Communication and Control

Functions of Relations

This is the set of processes by which our body obtains information from its environment and makes appropriate decisions.

Synaptic Elements

Presynaptic Element

Belongs to the cell that transmits the nerve impulse.

Synaptic Cleft

The space between neurons.

Postsynaptic Element

Belongs to the cell that receives the nerve impulse.

Types of Receptors

• Photoreceptors
• Thermoreceptors
• Mechanoreceptors
• Chemoreceptors
• Nociceptors

Skin Receptors

These include nociceptors, thermoreceptors, and mechanoreceptors.

Homeostasis: Maintaining Body Balance

The regulation of the body's internal environment, maintained within narrow limits by the nervous and endocrine systems.

Types of Nerve Cells

• Neurons
• Glia

Synapse

A structure through which a nerve impulse is transmitted from one neuron to another.

Nerves

Fiber extensions formed by bundles of neurons.

The Autonomic Nervous System

Responsible for regulating involuntary organ activities and is divided into the sympathetic and parasympathetic systems. The medulla oblongata controls involuntary functions such as breathing.

The Endocrine System and Hormones

Hyperthyroidism

A condition where the thyroid gland secretes too much thyroxine.

Hypothyroidism

A condition where the thyroid gland secretes too little thyroxine.

Endocrine System

Consists of a set of glands that produce hormones, which are released into the blood and act on certain organs.

Cellular Communication: Neurons

Sensory Neurons

Carry information from receptors to the central nervous system.

Motor Neurons

Send commands from the central nervous system to muscles and glands.

Interneurons

Are part of the central nervous system and connect sensory neurons with motor neurons.

The Locomotor System: Movement and Structure

Locomotor System

The system responsible for body movement, consisting of a passive part (the skeletal system) and an active part (the muscular system).

Skeletal System

The passive part of the locomotor system, made up of bones and cartilages.

Muscular System

The active part of the locomotor system, consisting of muscles and tendons that attach to bones and move them.

Osteogenesis

The process of bone formation.

Skeleton

A framework formed by bones and cartilage, linked together to allow movement. The periosteum is a membrane lining the outside of the bone.

Genetics and Life: DNA

DNA

Is a nucleic acid that contains genetic information.

Earth Science: Geology and Astronomy

Planetesimal Theory

Is the theory that explains the formation of planets.

Volcanoes and Volcanic Activity

A volcano is a rupture in the Earth's crust that allows molten rock, ash, and gases to escape from below the surface. Magma is molten rock inside the Earth. Products expelled by a volcano include gases, lava, and pyroclasts.

Fault

A rupture in large rocks where an earthquake originates.

Hypocenter

The point within the Earth where an earthquake originates.

Epicenter

The point on the Earth's surface directly above the hypocenter.