Understanding the Human Eye and Nervous System
Adnexia:
Lacrimal glands produce a slightly salty watery fluid that is responsible for keeping the eyeball moist. They contain lysozyme, an enzyme responsible for destroying certain bacterial agents.
Eyelids
Eyelids prevent the entry of foreign agents to the eye, such as dust and sweat. They are responsible for distributing tears all over the eyeball by blinking.
Muscles of the Eye
Muscles in the eye are responsible for moving the eyeballs up and down, left and right, and rotating them.
Eyeball:
- Sclera:
Anatomy and Physiology: Key Terms and Definitions
Regions of the Diencephalon
Located atop the brain stem and enclosed by the cerebral hemispheres, the diencephalon has three main parts:
- Thalamus: Relay station for sensory impulses.
- Hypothalamus: Regulates body temperature, controls water balance, regulates metabolism, and contains the limbic center.
- Epithalamus: Houses the pineal body.
Schwann Cells
These cells form a myelin sheath and provide support.
Brain Stem
Consisting of the pons and medulla oblongata, the brain stem is attached to the spinal cord
Read MoreArteries, Veins, Capillaries, and the Circulatory System
Arteries, Veins, and Capillaries
Arteries: Blood vessels through which blood flows, leaving the heart and distributing throughout the body. They are highly elastic and have three layers: tunica externa (connective tissue), internal layer (fine epithelial cells), and tunica media (smooth muscle fibers and elastic fibers).
Veins: Blood vessels where blood circulates from the capillaries towards the heart. Semilunar valves prevent backflow of blood.
Capillaries: Blood vessels between veins and arteries.
Read MoreGenetics: Inheritance and Mendel’s Laws
Genetics is a branch of biological sciences that aims to study patterns of inheritance—how traits and characteristics are passed from parents to children. Genes are segments of DNA.
Genotype vs. Phenotype
- Genotype: The set of hereditary genetic constitution of an organism.
- Phenotype: In biology and health sciences, the phenotype is the expression of the genotype in a given environment.
Homozygous and Alleles
- Homozygous: An individual whose genotype has a pair of identical genes (also known as a pure
Health Concerns: Diet, BMI, Diseases & More
Importance of a Balanced Diet
A varied diet ensures that the alimentation is balanced and contains all necessary nutrients. Corn, potatoes, and vegetables must be the basis of the alimentation.
Life Expectancy
Life expectancy is the average damage that a person is expected to live. Life expectancy can change throughout a person’s life.
Body Mass Index (BMI)
Body Mass Index (BMI) is the ratio between a person’s weight (in kilograms) and height (in meters squared). The value obtained is not constant but
Read MoreCellular Physiology: Transport, Respiration, and Division
Cellular Physiology
It deals with the study of each and every one of the functions performed by the cells. The most important focuses on the movement of substances across their membranes, which form the barrier between the intracellular and extracellular fluid.
Passive Transport
Passive transport involves the movement of substances in different media concentration with no need to expend energy.
- Simple diffusion: Moving from a place of higher to lower concentration.
- Facilitated diffusion: Large molecules