The Human Body chapter 1

Anatomy

Study of the structure of body parts and their relationship to one another

Gross/Macroscopic

Reigonal, System, Surface

Microscopic

Cytology, Histology

Developmental

Embryology

Physiology

Study of the function of body parts; how they work to carry out life-sustaining activities

Based on organ systems

Often focuses on cellular and molecular levels of the body

Looks at how the body’s abilities are dependent on chemical reactions in individual cells

The two are Inseprable

- Function always reflects structure
- What a structure can do depends on its specific form
- Known as the principle of complementarity of structure and function

Chemical Level

Atoms, Molecules, Organelles

Cellular Level

Single Cell

Tissue Level

Groups of Similar Cells

Organ Level

Contains 2+ Types of Tissues

Organ System

Organs That Work Closely Together

Organismal Level

All Organ Systems Combined to Make the Whole Organism

Maintaining Boundaries

Separation between internal and external environments
(E,g Plasma membranes, Skin separates organism from environment)

Movement

The muscular System allows movement
of body parts via skeletal muscles and of substances via cardiac muscle (blood) and smooth muscle (digestion, urination)

Responsiveness

Ability to sense and respond to stimuli

Digestion

Mechanical and enzymatic breakdown of ingested food, followed by absorption of simple molecules (monomers) into blood/lymphatics

Metabolism

All chemical reactions that occur in body cells. Sum of all catabolism (breakdown of molecules) and anabolism (synthesis of molecules)

Excretion

Removal of wastes from metabolism and digestion E.g
Urea (from breakdown of proteins), carbon dioxide (from metabolism), feces (unabsorbed food)

Reproduction

At the cellular level, reproduction involves the division of cells for growth or repair
At the organismal level, reproduction is the production of offspring

Growth

Increase in size of a body part or of the organism

Integumentary System

Synthesizes vitamin D and houses pain, pressure, etc receptors along with sweat and oil glands

Hair, Skin, Nails

Skeletal system

Protects and supports body organs. Blood cells are formed within bones

Bones, Joints

Muscular System

Allows manipulation of the environment, locomotion, facial expression, etc

Muscles in body: Obliques, Biceps, Pec

Nervous System

Responds to internal and external changes by activating appropriate muscles and glands

Nerves, Brain, Spinal cord

Endocrine System

Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use

Ovary, Testis, Adrenal gland, Pancreas

Cardiovascular System

Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood

Blood Vessels, Heart

Lymphatic system

Picks up fluids leaked from blood vessels and returns it to blood. Houses white blood cells (involved with immunity).

Redbone Marrow, Thymus, Spleen, Lymph nodes

Respiratory System

Keeps blood constantly supplied with oxygen and removes carbon dioxide. Occurs within the walls of the lungs

Lungs, Nasal Cavity, Pharynx, Trachea, Bronchus

Digestive System

Breaks down food into absorbable units that enter the blood for distribution to body cells. Indigestible food are eliminated as feces

Liver, Stomach, Large/Small Intestine

Urinary System

Eliminates nitrogenous wastes from the body. Regulates water, electrolyte, and acid-base balance of the blood

Urinary Bladder, Kidney, Urethra

Male Reproductive System

Overall function is production of offspring. Testes produce sperm and male sex hormones

Prostate, Penis, Testis, Scrotum, Ductus deferens

Female Reproductive System

Overall function is offspring. Ovaries produce eggs and female sex hormones

Mammary glands, Ovary, Uterus, Vagina, Uterine tube

A body cavity is a fluid-filled space inside the body that holds and protects internal organs

Body contains internal cavities that are closed to an environment
Cavities provide different degrees of protection to organs within them

Two sets of Cavities

Dorsal Body Cavity

Cranial Cavity

Vertebral Cavity

Ventral Body Cavity

Abdominal Pelvic Cavity

Pleural Cavity

Membranes in the ventral body cavity
→ Serosa (also called serous membrane
Thin, double-layered membranes that cover surfaces in the ventral body cavity

-Parietal serosa lines internal body cavity walls

-Visceral serosa covers internal organs (viscera)
Double layers are separated by a slit-like cavity filled with serous fluid
Fluid secreted by both layers of membrane

surfaces along which body or structures may be cut for anatomical study
→ Three most common planes:
Sagittal Plane
Frontal (coronal) plane
Transverse Plane

Sagittal Plane
→ Divides body vertically into right and left parts
→ Produces a sagittal section if cut along this plane

Midsagittal (median) plane
→ The cut was made perfectly on the midline

Parasagittal Plane
→ The cut was off-centered, not on the midline

Frontal (coronal) plane
→ Divides body vertically into anterior and posterior parts (front and back)
→ Produces a frontal or coronal section

Transverse (Horizontal) plane
→ Divides body horizontally (90° to the vertical plane) into superior and inferior (top and bottom)
→ Produces a cross-section

Oblique Section
→ Result of cuts and angles other than 90° to a vertical plane

Sections
→ cuts of sections made along a body plane

Standard Anatomical Position
→ Body erect, feet slightly apart, palms facing forward with thumbs pointing away from the body

Directional Terms describe one body structure in relation to another body structure
→ Direction is always based on standard anatomical position
→ Right and left refer to the body being viewed, not right and left of the observer

PICTURE https://medictests.com/units/standard-anatomical-terms-and-planes

Regional Terms

Regional terms designate specific areas within body divisions

Axial
→ Head, neck, and trunk

Appendicular
→ Libs (legs and arms)

Homeostasis is the maintenance of relatively stable internal conditions despite continuous changes in environment

Any self-regulating process by which an organism tends to maintain stability while adjusting to conditions that are best for its survival

The body must constantly be monitored and regulated to maintain homeostasis
→ Nervous Systems
→ Variables

Homeostatic Controls

Receptor (sensor)
- Monitors environment
- responds to stimuli

Control Center
- Determines set point at which variable is maintained
- Receives input from receptor

Effector
- Receivers output from the control center
- Provides the means to respond

Negative Feedback
- Most-used feedback mechanism in the body
- Response reduces or shuts off original stimulus
- Variable changes in opposite direction of initial change
1. Regulation of blood glucose by insulin
2. Regulation of body temperature

Regulation of blood glucose
– Receptors sense increased blood glucose (blood sugar)
– Pancreas (control center) secretes insulin into the blood
– Insulin causes body cells (effectors) to absorb more glucose, which decreases blood glucose levels

Positive Feedback
- Response enhances the original stimulus
- May exhibit a cascade or amplifying effect as feedback causes variable to continue in the same direction as the initial change
- Usually controls infrequent events that don’t require continuous adjustment
1. Enhancements of labor contractions by oxycontin
2. Platelet plug formation and blood clotting

Homeostatic Imbalance

Disturbance of homeostasis
→ Increases risk of disease: pathology
→ Contributes to changes associated with aging

Control systems become less efficient
→ If negative feedback mechanisms become overwhelmed, destructive positive feedback mechanisms lower
→ e.g heart failure

Serous membranes can become inflamed as a result of infection or other causes

Normally smooth layers can become rough and even can stick together, resulting in excruciating pain

Nutrients

Chemicals for energy and cell building
→ Carbs: Major source of energy
→ Proteins: Needed for cell building and enzyme activity
→ Fats: Long-term energy storage
→ Minerals and vitamins: involved in chemical reactions as well as for structural purposes

Oxygen

Essential for release of energy from foods
→ The body can survive only a few minutes without oxygen

Water

The most abundant molecule in the body: Provides the watery environment needed for chemical reactions
→ Also is the fluid base for secretions and excretions

Normal Body Temperature

If body temp falls below or goes above 37°C, rates of chemical reactions are affected

Atmospheric Pressure

Specific air pressure is needed for adequate breathing and gas exchange in the lungs