Human Body Systems and Health

Lymph Nodes and Nephrons

Lymph Nodes

Lymph nodes are made of lymphatic tissue located in specific areas of some lymphatic vessels. They make lymphocytes and release lymph plasma.

Nephrons

Nephrons are the structural and functional units of the kidneys. They are tubes with one closed end and are surrounded by blood capillaries. Nephrons are responsible for filtering blood and forming urine, regulating water and mineral content.

• Bowman's Capsule: Initial zone
• Convoluted Tube: Long twisted tube with two main parts, proximal and distal
• Loop of Henle: Section located between the proximal convoluted tube and the distal zone

Urinary System

Ureters

Ureters are thin tubes that start from each kidney and end in the bladder, an elastic bag in which urine accumulates.

Urethra

The urethra is a duct that connects the bladder with the exterior. Its end has a sphincter that remains closed except for when the micturition reflex occurs.

Urine

Urine is a liquid obtained from blood composed of water, minerals, and diverse waste products.

Nervous System

Cell Body

The cell body contains the nucleus and other organelles and is filled with cytoplasm.

Axon

The axon is a long extension made up of cytoplasm and carries nerve impulses.

Dendrites

Dendrites are short, branched extensions of the cell body that receive nerve impulses from neurons.

Structure

• Unipolar
• Multipolar
• Bipolar

Function

• Sensory: Transmit information from the receptors to the most important nerve centers
• Motor: Transmit the signals from the nerve center to the effector organs
• Interneurons: Connect the sensory neurons and the motor neurons, brain, and spinal cord

Spinal Bulb

The spinal bulb makes up the extension of the spinal cord, areas of gray matter surrounded by white matter.

Brain Stem

The brain stem is located between the spinal bulb and the cerebrum. It regulates sleep, visual and auditory reflexes, blood pressure, and communication between the cerebrum and other parts of the brain.

Cerebellum

The cerebellum is found in the back of the brain, made up of gray matter on the outside and white matter inside.

Cerebrum

The cerebrum is the largest part of the brain. Gray matter forms the cerebral cortex, responsible for acquired behavior.

Sensory Organs

Eye

The eye is the organ where the sense of sight is located. It is a complex structure that receives light and carries it to the area where the photoreceptors are located.

• Cornea
• Aqueous humor
• Pupil
• Lens
• Vítreous humor
• Retina
• Optic nerve

Ear

Outer Ear

The outer ear is formed by the pinna and auditory canal, an elastic membrane, and the eardrum.

Middle Ear

The middle ear contains the oval window, round window, hammer, anvil, and stirrup, which transmit sound waves from the eardrum to the inner ear.

Inner Ear

The inner ear consists of the membranous labyrinth, bony labyrinth, perilymph, and endolymph.

• Knowledge of the Body Position: Occurs in the utricle and saccule when we're motionless
• Detecting Movement: Allows us to move, occurs in the semicircular canals

Skeletal System

Long Bones

Long bones are long and contain spongy bone tissue at either end as well as compact bone. They support and move the body.

Health

Health is the complete physical, mental, and social well-being, not only the absence of disease.

Cause-Organic Alteration-Symptoms and Signs-Cure

Preventive Medicine

Vaccination

Vaccination is a very effective method to prevent some infectious diseases and has saved countless lives.

Tolerance and Dependency

• Tolerance: Capacity of the body to develop resistance to a toxic substance and adapt to it after prolonged consumption
• Dependency: Is the need our body has to consume a drug in order to function properly

• Physical
• Psychological

Stem Cells

Stem cells are progenitor cells that can regenerate one or several types of cells.

• Embryonic: Can develop into any type of cell
• Adult: Present in different organs and only produce certain types of cells

Microorganisms and the Immune System

Microorganisms that get into a healthy body

Transmission

• Direct contact
• Touching inert objects
• Drinking water
• Eating contaminated food
• The air
• Animals

Inflammatory Response

The inflammatory response is a non-specific defense mechanism. When pathogens get through the external barriers, the blood cells dilate to increase the blood flow.