Ch 1 - A&P Intro

Define human anatomy

the study of internal and external structures of the body

Define human physiology

the study of the function of the structures in the body

What are the levels of structural organization and body systems in order?

chemical level, cellular level, tissue level, organ level, organ systems level, and organism level

Describe the chemical level of organization

it’s the smallest level of organization and includes atoms and molecules

Describe the cellular level of organization

several molecules combine to form functional components that will work together as cells and form organelles

Describe the tissue level of organization

two or more cells that come together to perform a common function as a tissue. They are made up of two components: cells and extracellular matric (ECM)

Describe the organ level of organization

tissues that work together to form an organ, which also gives an identifiable structure and performs specialized tasks.

• ex: heart, skin, bones of the skeleton, etc.

Describe the organ system level of organization

the body’s organs are grouped into organ systems and they consist of two or more organs that carry out a broad function in the body

• ex: the cardiovascular system, where the heart and blood vessels work together to transport and deliver blood throughout the body

Describe the organism level of organization

the organ systems function together to make up a working human body (AKA organism)

Define histology

histology is the science that studies the microscopic structure of tissues

Define cytology

the study of structure & function of cells

What are the different types of anatomy?

systemic anatomy, regional anatomy, surface anatomy, gross anatomy, and microscopic anatomy

Describe systemic anatomy

the study of the body’s organ systems and their functions

• ex: skeletal system, muscular system, nervous system, etc.

Describe regional anatomy

the study of the body by specific areas (regions)

• head and neck, thorax (chest), abdomen, pelvis, upper limbs (shoulder→ head), lower limbs (hip → feet)

Describe surface anatomy

the study of external features on the surface of the body to locate internal structures

Describe gross anatomy

the study of structures that can be seen with the unaided eye - organs and organ systems

Describe microscopic anatomy

the study of structures that can only be seen with the aid of a microscope

• has specialized fields: histology and cytology

What are the planes of section and what are the 3 primary planes of section?

the standard ways of dividing a body or body part to examine its internal structure

• the sagittal plane, frontal plane, and transverse plane

Describe the Sagittal plane

it divides the body/body part into right and left sections and has two variations:

1. midsagittal plane (median plane, not the same as medial): divides the body/body part into equal right and left halves

2. parasagittal plane: divides the body/body part into unequal right and left halves

Describe the frontal plane

AKA the coronal plane and it divides the body/body part into anterior and posterior sections

• easy to remember because the frontal plane gives a front section and back section

Describe the transverse plane

AKA the horizontal plane or cross section and it divides the body/body part into superior and inferior parts. it also divides the appendicular region into proximal and distal parts

What is an oblique plane?

a less standardized plane, is taken at an angle and is useful for examining structures that aren’t easy to study with the standard planes of section

What are cavities?

a cavity is any fluid-filled space within the body

• body cavities both protect internal organs and allow them to move/expand when necessary

What are the two major cavities?

posterior body cavity and anterior body cavity

What two subcavities lie within the posterior body cavity?

Cranial cavity and the Vertebral/Spinal cavity

Where and what is the function of the cranial cavity

located within the skull and protects the brain

Where and what is the function of the vertebral/spinal cavity?

located within the vertebral column and protects the spinal cord

What fluid does the cranial cavity and vertebral/spinal cavity contain?

both have a fluid called “cerebrospinal fluid” (CSF)

• it bathes both organs and keeps the brain buoyant within the skull

The anterior body cavity’s two main divisions are separated by,,?

the diaphragm

What is superior to the diaphragm?

the thorax; which is known as the thoracic cavity

What is inferior to the diaphragm?

the abdomen pelvis; which is known as the abdominopelvic cavity

What are the 3 subcavities of the thoracic cavity?

• pleural cavity

• mediastinum

• pericardial cavity

What are pleural cavities?

there’s right and left PC and they each surround one lung and they’re located within serous membranes

What are mediastinum?

they are between the pleural cavities and it houses the heart, great blood vessels, trachea, and esophagus

• NOT located within a serous membrane

What is the pericardial cavity?

it’s inferior to the mediastinum and within a serous membrane; it also surrounds the heart

What are the two subcavities of the Abdominopelvic cavity?

• abdominal cavity

• pelvic cavity

what organs does the abdominopelvic cavity contain?

it contains organs of multiple systems, including the digestive, lymphatic, reproductive, and urinary system

• below the diaphragm

what subcavity can the organs of the abdominopelvic cavity also be in?

the peritoneal cavity, which is a abdominal subcavity and found within a serous membrane

What organs does the pelvic cavity contain?

organs of several systems, including the reproductive, digestive, and urinary systems

• contains reproductive organs

What are the 4 quadrants of the abdominopelvic cavity and where do they cross?

• Right Upper Quadrant (RUQ)

• Left Upper Quadrant (LUQ)

• Right Lower Quadrant (RLQ)

• Left Lower Quadrant (LLQ)

they cross at the umbilical region/umbilicus

What are the 9 segments of the abdomonipelvic cavity? (upper region)

• Right and Left hypochondriac region

• epigastric region

Where is the right/left hypochondriac region located?

they lie below the cartilage of the ribs

Where is the epigastric region located?

in between the right/left hypochondriac region and superior to the stomach

What are the 9 segments of the abdominopelvic cavity? (middle region)

• Right and Left lumbar region

• Umbilical region

Where is the right/left lumbar region located?

approximately the same region as the lumbar vertebrae

Where is the umbilical region located?

in the center of the abdomen, between the right/left lumbar region and contains the umbilicus

What are the 9 segments of the abdomonipelvic cavity? (lower region)

• Right and Left iliac region

• Hypogastric region

Where are the right/left iliac region located?

named for the anatomical regions over which they lie, the lower abdomen

Where is the hypogastric region located?

it’s between the right/left iliac region and inferior to the stomach

What are serous membranes and what organs do they contain?

they are formed by thin sheets of tissue within the anterior body cavity and they fold themselves to to make a continuous double-layer structure with space between their layers

• contains the heart, lungs, and many abdominal organs

What are serous fluids and what is their function?

they are within the layers of serous membranes and it’s a water, slippery liquid produced by the cells within the serous membrane

• they function to lubricate organs in the cavity to prevent friction as the organs move against adjacent structures

What are the 2 layers of serous membranes?

• Visceral layer (inner layer)

• Parietal layer (outer layer)

What are the 3 main serous membranes?

• pleural membranes

• pericardial membranes

• peritoneal membranes

What is homeostasis?

the body’s ability to maintain a relatively stable internal environment

What are feedback loops?

a change in a regulated variable causes effects that feed back and in turn affect that same variable

What is negative feedback?

one of the primary mechanisms for the maintenance of homeostasis and it opposes the initial change in a regulated variable and reduces the output

• negates any stimulus that moves a variable away from homeostasis

What is a positive feedback?

less common than negative feedback loops. the effector activity increases and reinforces the initial stimulus and shuts off when conditions return to the normal range

• a continuous loop - increases the response to a stimulus

What is a set point in feedback loops?

it’s basically the normal value. how normal body temps are 37 degrees C or normal BP is 110/70

• in reality, it’s a normal range around that certain set point

set point → the target value a system aims to maintain

normal range → the safe fluctuation zone around that target

What are receptors (sensors) in feedback loops?

when a regulated variable is outside its normal range, the information is picked up by the stimulus is picked up by the receptor (sensor)

What is the control (integrating) center in feedback loops?

where it processes the information sent from receptors and determines the appropriate response to restore balance in the system

What is the effector in feedback loops?

the organ that causes the physiological responses that returns the variable to the normal/stable range

• where the control center sends the message to

Variables in feedback loops are…

anything that can change and affect the system

What are the 4 core principles of anatomy?

1. feedback loops

2. relationship between structure and function

3. gradients

4. intercellular (cell-cell) communication

What is a gradient?

It’s when more of something exists in one area than another and the two areas are connected; they drive many psychological processes

What are the different examples of gradients?

• temperature gradient

• concentration gradient

• pressure gradient

How do cells communicate with one another and explain why it’s necessary for multicellular organisms

They communicate through electrical signals or chemical signals and it’s necessary to coordinate activities, maintain homeostasis, and facilitate responses to changes in their environment

What is electrical signals?

typically transmitted directly between neighboring cells

What is chemical messages?

they are released from one cell directly onto another cell or into the fluid surrounding another cell, or they can reach another cell through the blood

What are the 5 types of communication?

• direct communication

• autocrine communication

• paracrine communication

• endocrine communication

• synaptic communication

Describe direct communication

• signals are transmitted through gap junctions

• chemical mediators are ions, small solutes, lipid soluble materials

• distribution effects are usually limited to adjacent cells of the same type that are interconnected by connexons

Describe autocrine communication

• transmitted through ECF

• chemical mediators are autocrines

• distribution effects are limited to the cell that secretes the chemical mediator

Describe paracrine communication

• transmitted through ECF

• chemical mediators are paracrines

• dnearly cells with receptor binds to chemical and changes activity

Describe endocrine communication

• transmitted through the bloodstream

• chemical mediators are hormones

• distribution effects can be widespread (tissues/organs) and needs a receptor for the hormone

Describe synaptic communication

• transmitted across synapses via neurotransmitters

• chemical mediators are neurotransmitters

• distribution effects are limited to a single synapse. the target cell must have an appropriate receptor