Topic 16: Introduction To Human Biology

Biological Organization

- cells are the smallest unit of measurement of life

- cells are organized into tissues (epithelial, connective, muscle, nerve)

- tissues are organized into organs (eg.  stomach, heart) which comprise dissimilar combinations of tissues

- organs organize to shape organ systems (eg. digestive system, circulatory system)

- a collection of organ organization forms a complex organism (eg. human)

Homeostasis

-  the maintenance of a constant internal surroundings through the coordinated activities of dissimilar organs. eg. maintaining a constant trunk temperature

- a homeostatic mechanism requires a sensor to honor changes inward conditions as well as an effector machinery that tin vary the condition.  The connective betwixt the 2 is called negative feedback.

Source:  https://bitacoradeldante.blogspot.com//search?q=

- eg. temperature rule inward endotherms:  body temperature drops (due to mutual frigidity atmospheric condition conditions), organism reacts past times constricting peripheral blood vessels as well as shivering to attain extra estrus (over a longer period, the beast may attain a thicker "winter" coat)

Source:  http://www.tokresource.org/tok_classes/biobiobio/biomenu/nerves_hormones_homeostasis/index.htm

- Here is or as well as therefore other event of negative feedback

Source:  http://www.tokresource.org/tok_classes/biobiobio/biomenu/nerves_hormones_homeostasis/index.htm

-Positive feedback also exists.  In positive feedback systems, the effector enhances or increases the master stimulus.  One event is blood clotting (Bernat's favourite example).  When at that topographic point is an injury to a blood vessel, platelets adhere to the site as well as liberate chemicals.  These chemicals attract to a greater extent than platelets, which liberate to a greater extent than chemicals, which attract to a greater extent than platelets until the intermission is completely sealed.