Kin 2011 will cover the chemical, cellular, tissue, and organ functions in the human body.
Basic Cell Function
Food + O2 Food + O2 CO2 + H2O + Energy CO2 + Waste
Outside of Cell Inside of the cell Outside of the cell
- Cells have a mechanism that can help them control the exchange of material in side the cell
and the cell’s surrounding environment. Cells are able to synthesize what they need, and are
able to reproduce (exceptions are nerve & muscle cells).
- When the human is a fetus, it is composed of undifferentiated stem cell. They are cells that
don’t know what they want to become (eg. Heart cells or brain cells). Later they differentiate to
the four primary types of tissues.
The Four Primary Types of Tissues
-Consist of cells
Muscle Tissues Epithelial Tissues specialized for initiating
-They contract to generate force, -consist of cells specialized for Connective Tissues & transmitting electrical
exchanging materials btwn the -Connect and support impulses.
and are made of 3 types: cell and its environment. They body parts. -Found in brain, spinal
1-Skeletal muscles (moves the -Distinguished by having cord, and nerves.
skeleton) consist of 2 types: few cells spread within a
2-Cardiac Muscles (pump blood 1- Epithelial sheets (e.g. skin, GI
out of heart) tract) lot of extracellular
2- Secretory glands. Secretory material (E.g. tendons,
3-Smooth Muscles (Surround & glands arise from an invagination bone, and blood).
control movement of molecules
through hollow tubes and of the surface of the epithelial
organs). cell. They consist of 2 types:
a) Exocrine glands: release
substance through a duct to the
outside (the surface).
b) Endocrine glands: release
substance to the inside (the
blood), since their connecting
cells to the surface were lost. - A body system is a system where organs work together to function; the system does not work if
one organ is missing. The human body has 11 systems.
(Know which system is
which and what it is made up of, the function of these systems is explained in the next page)
Homeostasis: is the maintenance of the internal environment in a relatively stable range,
using feedback mechanisms. Each cell contributes to this internal stable environment,
whether it is pH, temperature, water conservation ... etc.
Negative feedback: is when the body proceeds to stop something because of too much of it.
Positive feedback: is when the body proceeds to increase the release of something because
it needs more of it.
Body cells live in a watery environment. Cells live in extracellular fluid (fluid outside the cell).
This outside fluid consist of interstitial fluid (mainly water), and plasma (blood). Moreover,
the cell also has fluid within itself, this is called intracellular fluid. This wonderful structure is
made so specific molecules can be transported in and out of the cell, thereby maintaining
the cells in a stable environment (Homeostasis)
-Homeostasis regulates the concentrations of nutrient molecules, O2 & CO2, water, salt, other
electrolytes, and waste products. It also regulates Volume, pressure, temperature, and pH.
-Disruption of homeostasis can lead to illness or death. Example of this is liposuction, since
liposuction involves the removal of body fluid as a side effect. Hypovolemic is the case where too much
fluid is removed which leads to death because of inadequate circulatory volume to sustain normal
homeostasis. In conclusion, homeostasis is essential for the survival of the cells, the body system
maintains homeostasis, and cells make up the body system. So, homeostasis is essential for the survival
Body systems and their functions (11 Systems): 1-Nervous system: transports information from the external environment and then acts through
electrical signals to control rapid responses of the body; also it is responsible for higher functions like
memory and creativity in the brain.
2-Respiratory system: obtains O2 from and eliminates CO2 to the external environment; helps regulate
pH by adjusting the following formula, CO2 + H2 H2CO3 HCO3 + H+ (this is called the
3-Urinary system: It consists mainly of the kidney. It is important in regulating volume, electrolytes
(metal ions, like sodium) composition, pH of internal environment; removes excess water, salt, acid from
the plasma and eliminates them in urine.
4-Digestive system: obtains nutrients, water, and electrolytes from the external environment (the cavity
from the mouth to the anus) and transfers them into the plasma, eliminates undigested food residue to
the external environment.
5-Reproductive system: it is not essential in maintaining homeostasis but essential for survival of the
6-Circulatory system: transports nutrients, O2, Co2, wastes, electrolytes, and hormones throughout the
7-Endocrine system: acts by means of hormones secreted into blood to regulate processes that require
duration rather than speed (e.g. metabolic activities and water & electrolyte balance)
8-Integumentary system: it keeps the foreign particles out by serving as a protective barrier between
the external environme