Chapter 1 - The Human Body

Anatomy

The various structures of the body, and their relationship to one another

Gross anatomy

Structures visible to the naked eye

What is connected to what in which cavity

Regional vs Systemic

Microscopic anatomy

Structures that are microscopic

Not visible to the naked eye

• Cells and tissues

Cytology vs histology

Physiology

How these individual body parts work (or function) on a normal level

Fixed in function

Mostly cellular and molecule

• Cell are the ones producing products

What is the relationship between structure and function?

Principle of complementarity of structure and function

What a structure can do is dependent on its form

Change structure → change function

Structural organization of the human body

1. Chemical

2. Cellular

3. Tissue

4. Organ Level

5. Organ System

6. Organismal Level

Chemical level

Atoms combine to form molecules

The smallest structural organization

Cellular level

The smallest unit of life

The 2nd structural organization

Tissue level

Aggregation of living cells that carry out a similar function

Four basic types

The 3rd structural organization

Types of tissue

• Muscle

• Epithelial

• Nervous

• Connective

Organ Level

2 or more tissues operate together to preform a certain function

The 4th structural organization

Organ System

Multiple organs work together to accomplish a purpose

The 5th structural organization

Organismal Level

All organ systems working together to keep the organism alive

(you as a person)

The last structural organization

Necessary Life Functions

1. Maintaining boundaries

2. Movement

3. Responsiveness

4. Digestion

5. Metabolism

6. Excretion

7. Reproduction

8. Growth

Maintaining Boundaries (as a necessary life function)

• At the cellular level

  • Plasma membrane to keep contains of a cell together

• At the organismal level

  • integument/skin

    • hold everything in

    • prevent exposure from environment and bacteria/viruses

Movement (as a necessary life function)

Cooperation of skeletal and muscular systems to coordinate actions

• Conscious/voluntary

  • Skeletal muscular tissues

• Not conscious/involuntary

  • Smooth muscle tissue (hallow organs)

  • Cardiac muscle tissues

Responsiveness/Excitability (as a necessary life function)

Sensing environmental changes both internally and externally and responding to them

• Nervous system is primarily involved with excitability

  • Neurons

  • Highly specialized to be excitable

  • How brain perceives information and communicates with rest of body

• Muscle tissue cells

  • Have to respond quickly to allow us to move fast

    • e.x: if we touch a hot stove

Digestion (as a necessary life function)

Absorb nutrients

Food is broken down to simple molecules to be absorbed to blood and delivered to various tissues

Metabolism (as a necessary life function)

• Sun of all chemical reactions in organism

  • Catabolism

    • Break down

    • Take larger molecule and breaking it down into smaller part

    • ex: protien to amino acids

  • Anabolism

    • Build up

    • Take smaller molecules and combining them to make larger molecule

    • ex: amino acids to protein

  • Cellular respiration

    • Produce ATP

    • ex: glycolysis, Krebs Cycle, electron transport train,

Excretion (as a necessary life function)

Removal of waste produced during digestive and metabolic function

• Forms

  • solid waste (digestive)

  • exhale (respiratory waste CO2)

  • nitrogenous waste (urinary system)

• Built up waste can

  • kill a cell

  • interfere with cellular function

Reproduction (as a necessary life function)

• Cellular level

  • cells must divide for organism to survive

• Organismal

  • production of offspring

  • species survival

Growth

• Increase in the number of body cells

• Increase in size of individual cells themselves

• Building must occur faster than breakdown

  • rate of anabolic > rate of catabolic

difference between survival need and life functions

The survival needs are required to be able to carry out life functions

Survival Needs

1. Nutrient

2. Oxygen

3. Water

4. Endothermy

5. Atmospheric Pressure

Nutrients (as a survival need)

• Brought into body by ingestion

• Includes macro nutrients: carbohydrates, fats, proteins

  • Need to bring them in at large amounts throughout the day

• Includes micro nutrients: vitamins and minerals

  • Vitamins important for chemical reactions

  • e.g: B12 necessary for ATP products

  • Minerals (iron, zinc, calcium) are structural

Oxygen (as a survival need)

• Cells can only survive a few minutes without oxygen

• Electron transport train requires oxygen to make ATP

  • Electron transport train supplies >50% of our APT

Water (as a survival need)

• We are 60% water

• Provides environment for chemical reactions

  • Primary solvents for chemical reactions to occur in and use as part of the reactions

    • Hydrolysis

• Fluid base for secretions and excretions

Difference between a secretion and excretion

• Secretions

  • Removes something it produces

• Excretion

  • Waste

Endothermy (as a survival need)

Body temperature must be maintained for chemical processes to occur

We produce our own body heat

Atmospheric Pressure

• Required for respiratory function

  • Breathing and gas exchange

• Changing altitude can effect humans

  • e.x: altitude sickness

    • Suddenly breathing in less oxygen concentration (thin air)

Homeostasis

• Maintenance of a consistent internal state despite changes in external environment

• Maintenance is not a static state, hover in a range of expectable levels

• Accomplished by the work of virtually all organ systems

Control of homeostasis

• Mostly regulated by central nervous system (almost always the brain) and the endocrine system (hormones)

• Variable: what organ or function is being controlled or regulated, 3 parts involved in variable control

  1. Receptor

  2. Control Center

  3. Effector

• Controlled by negative feedback mechanism or positive feedback mechanism

Receptor (in control of homeostasis)

Some type of cell that receives information about the variable and sends a message to control center

Control center (in control of homeostasis)

Almost always the brain, sometimes the spinal cord

receives message from receptor, interpret it, then send out a response to an effector

Effector (in control of homeostasis)

Receives response from control center and carries it out

Negative feedback mechanism

• Cause the variable to change in a direction that is opposite of the initial change

• Prevents large changes, more stable

• e.x: thermoregulation, most hormones

Positive feedback loop

• Cause the original change of the variable to be enhanced (accelerates the change)

• Way less common, used in emerencys

  • Does not control events that require frequents, small adjustments

• e.x: labor, blood clotting

Imbalances in homeostasis

• Causes:

  • aging leads to homeostatic imbalance

    • control systems become less efficient, making us more susceptible to disease

  • cascade of events caused by positive feedback mechanisms can overpower negative feedback mechanisms

• Leads to disease or sickness

Reference point: anatomical position

Right vs left is always viewed in terms of the person being observed. not your own

Dorsal (posterior) (anatomical term)

Backside

e.x: vertical column

Ventral (anterior) (anatomical term)

Front/belly side

Lateral (anatomical term)

Further from the midline

e.x: ear is lateral to the eye

Medial (anatomical term)

Closer into the midline

e.x: eye is medial to the ear

Distal (anatomical term)

further from the point of origin

e.x: Wrist distal to elbow (point of origin is shoulder)

Proximal (anatomical term)

e.x: Elbow proximal to wrist (point of origin is shoulder)

Deep (anatomical term)

Further from skin

Superficial (anatomical term)

Closest to skin

Superior (anatomical term)

On top of

Inferior (anatomical term)

Below

Body planes

Sagittal

Transverse

Frontal

Sagittal

Divides body into left and right

Median/midsagittal plane divides the body exactly in half

Frontal

Divides body into anterior and posterior

Transverse

Divides body in superior and inferior parts

Cross section

Body cavities

Most organs are found in one of the body cavities

Dorsal body cavity

Ventral body cavity

Dorsal body cavity

• Protects organs of central nervous system

• Composed of the cranial cavity and spinal

Ventral body cavity

• houses visceral organs

• Composed of:

  • Thoracic cavity: contains heart and lungs

  • Abdominopelvic cavity: separated from thoracic cavity by diaphragm

Membranes of the ventral body

• Serous membrane

  • double-layered membrane

Serous membrane

• Layers:

  • Visceral serosa: innermost layer covering the organ

  • Parietal serosa: outer layer lining the body wall of the cavity

  • layers are separated by a small amount of serous fluid

• Named according to their location

  • Pericardium: surrounds heart

  • Pleura: surrounds lungs

  • Peritoneum: surrounds most organs of the abdominopelvic cavity

Visceral serosa

• Innermost layer covering the organ

Parietal serosa

Outer layer lining the body wall of the cavity

Pericardium

Serous membranes surrounding the heart

Pleura

Serous membranes surrounding the lungs

Peritoneum

Serous membranes surrounding most organs of the abdominopelvic cavity

Do all organs have a serous membrane?

No, but most do

ex: Kidneys and esophagus do not