Human Body Systems and Functions
The Senses
The Sense of Sight
Components of the eye:
- Extraocular muscles
- Sclera
- Choroid
- Optic nerve
- Crystalline lens
- Iris
- Cornea
- Aqueous humor
- Vitreous humor
- Retina
The Sense of Hearing
Components of the ear:
- Pinna
- External auditory canal
- Eardrum
- Semicircular canals
- Cochlea
- Auditory nerve
- Eustachian tube
- Ossicles (chain of bones)
Coordination Systems
Nervous System
This system receives and transmits information rapidly by electrical impulses, through sensory neurons.
Endocrine System
This system consists of glands that secrete
Read MoreUnderstanding Cholesterol and Protein for Better Health
Cholesterol
Cholesterol can be synthesized by the body, absorbed by the intestine, and causes excess cardiovascular problems.
HDL cholesterol collects in the arteries and transports it to the liver. Exercise and moderate alcohol consumption increase HDL, while smoking decreases it.
Functions of Cholesterol
- Synthesis of steroid hormones
- Synthesis of bile acids necessary for the absorption of fats
- Synthesis of vitamin D
- Formation of cell membranes
Protein
A protein is considered more complete the more amino
Body Composition, Energy Needs & Nutritional Health Factors
Body Mass Index (BMI)
Formula: BMI = Weight (kg) / Height (m)²
BMI Categories:
- 18.5 – 24.9: Normal weight
- 25.0 – 29.9: Overweight
- 30.0 – 39.9: Obese
- 40.0+: Very Obese (Morbidly Obese)
Waist Circumference & Health Risks
Measure around the smallest part of the waist.
Risk Thresholds (Waist Circumference):
- Men: Increased risk > 94 cm; High risk > 102 cm
- Women: Increased risk > 80 cm; High risk > 88 cm
Associated Health Risks:
- Diabetes (Type II)
- Non-communicable diseases (e.g., cardiovascular disease)
Autonomic Nervous System Divisions Compared
Somatic vs. Autonomic Nervous Systems
Somatic Nervous System (SNS)
- Single axonal pathway from CNS.
- Thick myelin fibers.
- Target organs: skeletal muscles.
- Effect of neurotransmitter: excitatory.
- Neurotransmitter at target site: always acetylcholine.
- No ganglia present.
Autonomic Nervous System (ANS)
- Preganglionic and ganglionic neurons.
- Effectors are glands and involuntary muscles.
- At least one ganglion located outside the CNS.
- Thin or unmyelinated fibers.
- Transmitted effect may be excitatory or inhibitory.
Shared
Read MoreBiofuels, Polymers, and Sustainable Materials
Understanding Biofuels
Biofuel is any liquid fuel produced from vegetable raw materials whose chemical characteristics can replace gasoline and diesel.
Types of Biofuels
Biodiesel
Biodiesel is a liquid synthetic biofuel obtained from natural lipids such as vegetable oils or animal fats.
Biodiesel Applications
- Vehicles (e.g., rental cars, food transport trucks, farm machinery, commercial freight vessels like ferries, yachts, sailboats)
- Home heating oil
- Electricity generators (often a superior alternative
Key Diseases and Medical Advancements
Major Health Topics
Diabetes
Type 1 Diabetes
The pancreas does not produce insulin. Caused by the action of several inherited genes; possible autoimmune origin. Requires chronic insulin treatment. Involves many blood glucose injections (and urine analysis). Requires careful management of sugar intake.
Type 2 Diabetes
Affects adults, often associated with obesity and an unhealthy lifestyle. The pancreas produces little insulin, or the effect of insulin is greatly diminished (insulin resistance). Treatment
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