Week 1 (Human Physiology) Flashcards
Human Physiology
study of the normal functioning of the human body
how systems of the human body work
connection between body systems and interdependencies
Levels of Structural Organization of the Body
Chemical Level – Atoms and molecules.
Cellular Level – The smallest living unit in the body.
Tissue Level – Groups of similar cells performing a function.
Organ Level – Structures with multiple tissue types working together.
Organ System Level – A group of organs that function together.
Organism Level – The entire living being.
Organ Systems of the Body & Functions
Integumentary System – Skin, hair, nails (protection, sensation).
Skeletal System – Bones, joints (support, movement).
Muscular System – Skeletal muscles (movement, heat production).
Nervous System – Brain, spinal cord, nerves (control & communication).
Endocrine System – Hormone-secreting glands (regulation of bodily functions).
Cardiovascular System – Heart, blood vessels (transportation of oxygen & nutrients).
Lymphatic System – Lymph nodes, spleen (immune defense, fluid balance).
Respiratory System – Lungs, airways (gas exchange).
Digestive System – Stomach, intestines (food breakdown, nutrient absorption).
Urinary System – Kidneys, bladder (waste removal, water balance).
Reproductive System – Ovaries/testes (reproduction).
Homeostasis
the existence and maintenance of a relatively constant environment within the body
occurs despite variations in the external environment
the ability to maintain relatively stable internal conditions
how the body maintains balance within each system
HOMEOSTASIS (External environment)
surrounding environment in which an organism lives
HOMEOSTASIS (Internal environment)
the fluid that surrounds the cell~ extracellular fluid (ECF)
ECF= interstitial fluid (IF) + plasma
life-sustaining exchanges are made through this fluid
HOMEOSTATIC CONTROL MECHANISMS
Negative (-) Feedback
(Maintains stability)
When temp ↑ → body sweats to cool down.
When temp ↓ → body shivers to warm up.
eg. body temp; blood glucose (sugar) levels; blood pressure
HOMEOSTATIC CONTROL MECHANISMS
Positive (+) Feedback
(Enhances a process)
When injured, platelets release chemicals to attract more platelets, forming a clot.
eg. blood clotting; childbirth (labour contractions)
HOMEOSTATIC CONTROL MECHANISM
1) STIMULUS
produces change in variable
2) RECEPTOR
detects change
3) INPUT
Information sent along afferent pathway to control center
4) OUTPUT
Information sent along efferent pathway to effector
5) RESPONSE
Of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level.
Average normal body temp
= 37 ºC
HOMEOSTATICALLY REGULATED FACTORS
concentration of nutrients
conc. of oxygen (O₂) and carbon dioxide (CO₂)
conc. of waste products
pH (measure of hydrogen ion conc.)
conc. of water (H₂O), salt, other electrolytes
volume and pressure
temperature
