Human Physiology Chapter 1

Physiology

the study of the function of living organisms

The Chemical Level

lowest level of organization; this includes atoms (carbon, oxygen etc..) and molecules (water, DNA)

The Cellular Level

includes cells which are the smallest living units of matter.

Tissues

groups of cells that work together to carry out similar functions. 

Four Primary Tissues in the Human Body

 Epithelial Tissues,Connective Tissues,Muscle Tissue,Nerve Tissue

 Epithelial Tissues

These cover surfaces, line hollow organs and makeup glands in the human body. Distinguish between exocrine and endocrine glands.

Connective Tissues

these are all made of cells, fibers and matrix. These tissues bind structures together (ligaments, tendon), transport materials (blood), provide support (bone) and protect (adipose, leukocytes).

Muscle Tissue

is capable of contracting. Specific types of muscle tissue include skeletal muscle, cardiac muscle and smooth muscle. 

Nerve Tissue

is composed of neuroglial cells and neurons. Neurons are specialized to generate and transmit information through the body in the form of electrical signals known as impulses.

Organs

structures that are composed of 2 or more tissues that work together to perform similar functions. 

Systems

groups of organs that work together to carry out similar functions

What are the 11 major organ systems in the human body? What organs are found in each system?

integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive systems.

integumentary system

Skin, hair, nails, and associated glands (e.g., sweat, sebaceous).

skeletal system

Bones, cartilage, ligaments, and joints.

muscular system

Skeletal muscles, tendons, cardiac muscle, and smooth muscle.

nervous system

Brain, spinal cord, and nerves.

endocrine system

Glands including the pituitary, thyroid, parathyroid, adrenal, pancreas, pineal, hypothalamus, ovaries, and testes.

cardiovascular system

Heart, blood vessels (arteries, veins, capillaries), and blood.

lymphatic/immune system

Lymph nodes, spleen, thymus, bone marrow, and lymph vessels.

respiratory system

Nose, pharynx, larynx, trachea, bronchi, and lungs.

digestive system

Mouth, esophagus, stomach, small intestine, large intestine, liver, gallbladder, and pancreas.

urinary system

Kidneys, ureters, bladder, and urethra.

reproductive system

Male: Testes, epididymis, vas deferens, prostate, and penis.

Female: Ovaries, fallopian tubes, uterus, vagina, and mammary glands.

The Organismic Level

the highest level of organization in the human body.

Organism

a living individual.

There are four major classes of cells that make up the Human Body. The four cell types include 

Neurons,Muscle Cells,Epithelial Cells,Connective Tissue Cells

Neurons

are typically elongated and branched.

Cell Body

contains the cellular organelles.

Dendrites

often highly branched, these carry impulses to the cell body of a neuron from other neurons.

Axons

singular structure that carries impulses away from the cell body of a neuron to effectors (muscles, glands) and other neurons.

Muscle cells

muscle cells are typically referred to as being muscle fibers

Skeletal Muscle Fibers

elongated cells that contain multiple nuclei. These cells are striated and voluntary. These cells attach to and move bones.

Cardiac Muscle Fibers

branched cells that contain one central nucleus. These cells are striated and involuntary. These cells create force in the heart.

Smooth Muscle Fibers

small, linear cells with one nucleus. These cells are involuntary and non-striated. These cell regulate movements through many of the internal organs.

Epithelial Cell Shapes

Squamous-small, flat

Cuboidal-squared shape

Columnar-column-shaped

Transitional-can change shape

Functions of Epithelial Cells

Cover surfaces-protect

Are involved in gas and liquid exchanges

Can protect via mucus production and cilia

Secretion of some materials (make up many glands)

            (Exocrine vs. Endocrine Glands)

Lining hollow organs such as the stomach and small intestine. The “hole” that the epithelium surrounds is known as the lumen.

Connective cells

come in a wide variety of shapes

Functions: Connect bones together (ligaments)

Anchor muscles to bone (tendons)

Support all body structures (bone)

Transport materials (blood)

Protect (adipose, leukocytes)

Simplified Human Body Plan

Epithelial cells separate the body’s internal and external environments.

Most cells receive oxygen and nutrients from the bloodstream through the internal environment.

Oxygen enters the blood in the lungs and carbon dioxide leaves during breathing.

Nutrients are absorbed in the small intestine, and wastes are filtered and excreted by the kidneys.

Homeostasis

the maintenance of a constant internal environment within the human body.

Organ systems work together to maintain homeostasis; disruption can cause disease or death, but the body can adapt to stress.

Water makes up about 60% of the human body and transports nutrients, solutes, and wastes.

Total Body Water (TBW)

the volume of water contained in all of the body’s compartments. In an average size person, this equates to about 42 liters of water. 

Intracellular Fluids (ICF)

Found inside cells and contained by the cell membrane.

Also called cytoplasm or cytosol.

Makes up about two-thirds of total body water.

Extracellular Fluids (ECF)

refers to fluid external to the cell membrane of cells. ECF makes up 1/3^rd of TBW.

Plasma

The liquid portion of blood.

Makes up about 20% of extracellular fluid (ECF).

Contains suspended blood cells and has a high protein content.

Interstitial Fluid (ISF)

The liquid found in body tissues, surrounding body cells. 

Composition of ECF vs. ICF

Sodium and Chloride ions are more abundant in ECF while potassium ions are most abundant in ICF. Also, proteins make up a greater proportion of  ICF.

 Feedback Systems

Internal control systems that restore homeostasis after a stressor.

Sensory nerves detect the change and signal the brain.

The brain activates effectors (muscles or glands) to produce a response.

Negative Feedback Systems

function by reversing the effects of a stressor on the body. 

Body temperature control (sweating or shivering)

Blood glucose control (insulin and glucagon)

Breathing rate control (carbon dioxide levels)

Positive Feedback Systems

function by increasing the effects of a 

    stressor on the body to restore homeostasis.

Childbirth – Oxytocin increases contractions until birth occurs.

Blood clotting – Platelets activate more platelets until the clot forms.

Nerve impulses – Sodium influx increases membrane permeability until the signal is sent.