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