Human Body Systems
Objectivesdefine anatomy and physiology and describe how they are interconnected
understand anatomical terminology
define homeostasis and outline the homeostatic control system
describe positive and negative feedback, include examples
Anatomyanatomy: the study of the structure and shape of the body and body parts
includes relationships of body parts to each other
gross anatomy: study of large, easily observable structures within the body
microscopic anatomy: requires a microscope or magnifying instrument to study the anatomy of very small body structures
Physiology
physiology: the study of how the body and its parts work or function
has many subdivisions of study:
neurophysiology
cardiac physiology
Organization
Recall: Cellssmallest unit of living things
in complex organisms like trees or human beings, cells are building blocks of the structural ladder
groups of related cells join together to create tissues
TissuesTissue: group of similar cells combined to perform a common function
The material formed from like cells
There are 4 types of tissue in the human body:
connective, muscular, nervous, and epithelial
Different types of tissues can comprise an organ
Various organs that work together to perform a function, are a system
OrgansOrgans: combination of two or more different tissues performing a common function
at this level of organization, extremely complex functions become possible
small intestine is an example of an organ with all 4 tissue types
organ system: a group of organs that cooperated to accomplish a common purpose
Anatomical Position
standard position, always assume the body is in this position
standing upright
feet parallel
arms at sides
palms facing forward
anterior: forward facing
posterior: backward facing
https://www.youtube.com/watch?v=KqgTERrYbQ4
Directional Terms
superior: in the direction towards the head
inferior: in the direction away from the head
Directional Terms
midline: reference line extending down the middle of the body (spinal cord, naval, vertebral column)
medial: toward the midline
lateral: away from the midline
Directional Terms
proximal: toward point of origin of body part in question
distal: away from the point of origin of body part in question
Homeostasisthe body’s ability to maintain relatively stable internal conditions regardless of the outside worlds continuous changes
dynamic state of equilibrium or a balance in which internal conditions change and vary but always within relatively narrow limits
every organ is system has a role in maintaining homeostasis
Homeostasis
ensures that the organs of the body operate within their normal limits thereby working efficiently
requires adequate blood levels and vital nutrients be continuously present along with heart activity and blood pressure
waste must not be allowed to accumulate and temperature must be precisely controlled
Homeostasisregulated by cues given via the endocrine and the nervous system
these cues create the control mechanisms for homeostasis regardless of what is being regulated
creates a feedback loop (positive or negative)
Control MechanismsReceptor: sensor that monitors and responds to changes in the environment (stimuli)
Control Centre: determines the response based on information received
Effector: provides the means to execute the response
Feedback is sent to the receptor which will either depress it (stop), or enhance it (continue)
Control Mechanisms
afferent pathway: moves the information from the receptor to the control centre
efferent pathway: moves information from control center to effector
negative feedback: stimulus stops
positive feedback: stimulus continues
https://www.youtube.com/watch?v=Iz0Q9nTZCw4
Negative Feedbackresult of most metabolic control mechanisms
Negative Feedback
Positive Feedbackrare in the body
Additional Resources
Easiest way to learn directional terms: https://www.youtube.com/watch?v=gxxy7AP_eGQ
The human body system and facts: https://www.youtube.com/watch?v=e_1utfWwdD4