BIO 360 - Animal Physiology (Exam 1)

Covers chapters 1, 3, 5, 6, and 8.

Physiology

The study of the typical functioning of a living organism and its component parts, including all its chemical and physical processes

Circulatory (cardiovascular) system

transport of materials between cells of the body

Digestive (gastrointestinal) system

conversion of food into particles that can be transported into the body; elimination of some waste

Endocrine system

coordination of body function through synthesis and release of regulatory molecules

Immune system

defense against foreign invaders; includes, but not limited to, the lymphatic system

Integumentary system

protection from external environment

Musculoskeletal system

support and movement

Nervous system

coordination of body function through electrical signals and release of regulatory molecules

Reproductive system

perpetuation of the species

Respiratory (pulmonary)

exchange of oxygen and carbon dioxide between the internal and external environments

Urinary (renal)

maintenance of water and solutes in the internal environment; waste removal

Anatomy

the study of body structures

Levels of organization

Cells, Cell Membrane (Plasma Membrane), Tissues, Organs, Organ Systems.  

Tissues

a collection of cells

Organs

tissues that formed structural and functional units

Organ Systems

a collection of organs that integrated their functions

Homeostasis

the regulation of the body’s internal environment

What are 10 variables that the body monitors and regulates?

Blood gates: oxygen and carbon dioxide

Blood solutes: Potassium [K+], Calcium [Ca2+], Hydrogen [H+] (pH), Glucose

Arterial blood pressure

Blood volume

Blood osmolarity

Body temperature (core)

Extracellular fluid (ECF)

serves as the transition between an organism’s external environment and the ICF

Intracellular fluid (ICF)

inside cells

Feedback loop

the response “feed back” to influence the input portion of the pathway

Response loop

has three primary components (input, integrating center, output) that can be expanded into the following sequence of seven steps

Negative feedback (loops)

a pathway in which the response opposes or removes the signal; is homeostatic; stabilizes the regulated variable and thus aid the system in maintaining homeostasis

Positive feedback (loops)

not homeostatic; response reinforces the stimulus rather than decreasing or removing it; the response sends the regulated variable even farther from its usual value

Feedforward control

reflexes that have evolved that enable the body to predict that a change is about to occur and start the response loop in anticipation of the change

Independent variable

the altered variable

Dependent variable

the non-altered variable that being measured

Cross-sectional study

examines a population for the prevalence of a disease or condition

Longitudinal study

An experimental designed to be carried out for a long-period of time

What are three major body cavities?

Cranial, Thoracic, and Abdominopelvic

Cranial cavity

commonly referred to as the skull; contains the brain

Thoracic cavity

also called the thorax; bounded by the spine and ribs on top and sides with the diaphragm forming the floor; contains the heart (enclosed in a membranous pericardial sac), the lungs (enclosed in separate pleural sacs)

Abdominopelvic cavity (abdomen and pelvis)

Peritoneum (a tissue lining) lines the abdomen and surrounds the organs w/n it (stomach, intestines, liver, pancreas, gallbladder, spleen); Kidneys are outside the cavity - between the peritoneum and muscles/bones of the back, above the waist level

Transcellular compartments

Aqueous and Vitreous Humors; Cerebrospinal fluid (CSF); Membranous sacs

Aqueous and Vitreous Humors

the compartments for the eyes

Cerebrospinal fluid (CSF)

the fluid that surrounds the brain and spinal cord

Membranous sacs

surrounds the lungs (pleural sacs) and the heart (pericardial sac); contains small volumes of fluid

Lumen

the interior of any hollow organ; may be wholly or partially filled with air or fluid; in some organs, it’s an extension of the external environment. It is not part of the body’s internal environment until it crosses the wall of the organ.

Phospholipids, Sphingolipids

Forms with Cholesterol to form Lipid Bilayer

Lipid Bilayer

selective barrier between cytosol and external environment

Carbohydrates

Forms with Phospholipids, Sphinolipids to create Glycolipids

Glycolipids

Structural stability, cell recognition, immune response

Proteins

Form with Carbohydrates to create Glycoproteins

Glycoproteins

Structural stability, cell recognition, immune response

Phospholipid bilayer

made of a glycerol backbone with two fatty acid chains extending to one side and a phosphate group extending to the other; Glycerol-phosphate head - polar, hydrophilic; Fatty acid “tail” - non polar, hydrophobic

Micelle

small droplets with a single layer of phospholipids arranged so that the interior is filled with hydrophobic fatty acid tails; important in the digestion and absorption of fats in the digestive tract

Liposome

larger spheres with bilayer phospholipid walls which leaves a hollow center with an aqueous core that can be filled with water-soluble molecules

Membranous organelles

Mitochondria, Endoplasmic reticulum, Golgi apparatus, Lysosomes, Peroxisomes

Nonmembranous organelles and inclusions

Ribosomes, Proteasomes, Centrosome, Lipid droplets, Glycogen granules

Protein fibers

Cytoskeleton, Centrioles, Cillia, and Flagella

Cytoskeleton

Microvilli, Microfilaments, Microtubles, Intermediate filaments

Microvilli

supported by actin microfilaments increase cell surface area

Microfilaments (actin fibers)

form a network just inside the cell membrane; associates with myosin for muscle contraction; 7mm in diameter

Microtubules (tubules)

the largest cytoskeleton fiber; Movement of cilia, flagella, and chromosomes; intracellular transport of organelles; 25mm in diameter

Intermediate filaments (keratin, neurofilament, etc.)

include myosin; hair and nails, protective barrier of skin; 10mm in diameter

Which cytoplasmic protein fibers provide strong mechanical support and help resist stretching?

Intermediate filaments

What are the 5 majors functions of the cytoskeleton?

1. Cell shape: provides mechanical strength to the cell and in some cells plays an important role in determining the shape of the cell

2. Internal organization: stabilize the positions of organelles, changing from minute to minute in response to the needs of the cell

3. Intracellular transport: helps transport materials into the cell and throughout the cytoplasm by serving as an intracellular “railroad track” for moving organelles; Especially important in neural cells (up to 1m long) 

4. Assembly of cells into tissues (Protein fibers link cells) 

5. Movement: helps cells move

Motor proteins

facilitate movement and intracellular transport by using energy from ATP to slide or step along the fibers; made of multiple protein chains arranged into three parts: two heads, a neck, and tail

Cilia

short projections of the cell surface like the bristles of a brush; Most cells have a single, stationary cilium; Moving cilia line the upper airways, portions of the reproductive tract, and CNS

Flagella

longer extensions found on free-floating single cells; sperm cell is the only flagellated cell

Steps of protein synthesis that uses subcellular compartmentation

1. mRNA is translated from genes in the DNA

2. mRNA leaves the nucleus and attaches to cytosolic ribosomes, which initiates protein synthesis

3. Some proteins are released by free ribosomes into the cytosol or are targeted to specific organelles

4. Ribosomes attached to the rough endoplasmic reticulum direct proteins destined for packaging into the lumen of the rough endoplasmic reticulum. 

5. Proteins are modified as they pass through the lumen of the ER.

6. Transport vesicles move the proteins from the ER to the Golgi apparatus. 

7. Golgi cisternae migrate toward the cell membrane

8. Some vesicles bud off the cisternae and move in a retrograde or backward direction

9. Some vesicles bud off to form lysosomes or storage vesicles

10. Other vesicles become secretory vesicles that release their contents outside the cell

Extracellular matrix

extracellular material synthesized and secreted by cells of a tissue; Composition varies from tissues to tissues; Determines mechanical properties (flexibility and elasticity); Has two basic components (proteoglycans and insoluble protein fibers)

Proteoglycans

glycoproteins, which are proteins covalently bound to polysaccharide chains

Insoluble protein fibers (collagen, fibronectin, and laminin)

provide strength and anchor cells to the matrix

Three major categories of cell junctions

Communication, occluding, anchoring

Communication junctions

allow direct cell to cell communication; includes gap junctions

Gap junctions

the simplest cell-cell junctions; Allows direct and rapid cell-to-cell communication through cytoplasmic bridges between adjoining cells; Allow both chemical and electrical signals to pass rapidly from one cell to the next

Occluding junctions

block movement of material between cells; includes tight junctions

Tight junction

restrict the movement of material between the cells they link; Creates the “BBB” that prevents many potentially harmful substances in the blood from reaching the extracellular fluid of the brain

What is the main function of tight junctions?

Prevent substances from leaking between neighboring cells

Anchoring junctions

hold cells to one another and to the extracellular matrix; contribute to the mechanical strength of the tissue; includes cell-cell and cell-matrix junctions

Adherens junction

bands that link actin microfilaments in adjacent cells together with the help of cadherins; cell-cell junction that’s part of anchoring junction

Desmosome

type of cell-to-cell junction; attach to intermediate filaments of the cytoskeleton; Strongest cell-cell junctions; May be small points of contact between two cells (spot desmosomes) or bands that encircle the entire cell (belt desmosomes); cell-cell junction that’s part of anchoring junction

Focal adhesion

intracellular actin fibers to different matrix proteins; cell-matrix junction that’s part of anchoring junction

Hemidesmosome

strong junction that ties a cell to matrix; anchors intermediate fibers of the cytoskeleton to fibrous matrix proteins; cell-matrix junction that’s part of anchoring junction

What is a common, inconvenient case in which anchoring junctions or desmosomes are disrupted?

A blister

Epithelial

protect the internal environment of the body and regulate the exchange of materials between the internal and external environments; Covers exposed surfaces and line internal passageways; Has multiple types: exchange, transporting, ciliated, protective, secretory

Exchange epithelium

Layer(s):  One cell layer

Shape: Flattened shape

Features: Pores between cells permit easy passage of molecules

Can be found: lungs, and lining of blood

Transporting epithelium

Layer(s): One cell layer

Shape: Columnar or cuboidal

Feature(s): Tight junctions prevent movement between cells…

Can be found: kidneys, intestine, some exocrine glands

Ciliated epithelium

Layer(s): One cell layer

Shape: Columnar or cuboidal

Feature(s): One side covered with cilia to move liquid across surface

Can be found: nose, trachea, upper airways; female reproductive tract

Which type of epithelium lines much of the respiratory tract, including the trachea?

Ciliated epithelium

Protective epithelium

Layer(s): Many

Shape: Flattened in surface layers; polygonal in deeper layers

Feature(s): Cells tightly connected by many desmosomes 

Can be found: Skin and lining of cavities that open to the environment (such as the mouth)

Secretory epithelium

Layer(s): One to many

Shape: Columnar or cuboidal

Feature(s): Protein-secreting cells fill with membrane-bound secretory granules and extensive RER; steroid-secreting cells contain..

Can be found: Exocrine glands, salivary glands, pancreas, endocrine glands (thyroid and gonads)

Connective

provide structural support and sometimes a physical barrier that helps defend the body from foreign invaders; includes blood, support tissues for the skin and internal organs, cartilage, and bone; Has multiple types: Loose connective tissue, Bone and cartilage, Dense connective tissue, Blood, Adipose

Muscle and Neural

called excitable tissues due to their ability to generate and propagate electrical signals called action potentials

Chemical disequilibrium

ions are not equally distributed across the cell membrane

Electrical disequilibrium

inside the cell is more negatively charged

Molarity

number of moles of dissolved solute per liter of solution (mol/L); expresses concentration

Osmosis

the movement of water across a membrane in response to a solution gradient

Osmolarity

the number of osmotically active particles (ions or intact molecules) per liter of solution (per liter); Expressed in osmole per liter (osmol/L or OsM) or for very dilute physiological solutions (milliosmoles/liter [mOsM];

Osmolality

concentration expressed as osmoles of solute per kilogram of water (per kg); Usually used in clinical situations because it’s easy to estimate people’s body water content by weighing them; A colligative property of solutions - it depends strictly on the number of particles per liter of solution; A property of every solution

Isosmotic

If two solutions contain the same number of solute particles per unit volume

Hyperosmotic

If solution A has a higher osmolarity (contains more particles per unit volume, is more concentrated) than solution B - solution A is hyperosmotic to solution B

Hyposmotic

If solution A has a higher osmolarity (contains more particles per unit volume, is more concentrated) than solution B. Solution B has fewer osmoles per unit volume - solution B is hyposmotic to solution A

Tonicity

a physiological term used to describe a solution and how that solution would affect cell volume if the cell were places in the solution and allowed to come to equilibrium

Hypotonic

a cell when placed in the solution gains water at equilibrium and swells

Isotonic

a cell in solution does not change size at equilibrium

Hypertonic

a cell loses water in solution and shrinks at equilibrium

What happens to an animal cell placed in a hypotonic solution?

It gains water and may burst

What happens in this situation?

You have a membrane permeable to urea and water but not to NaCl. On side A, you have a urea solution, and on side B, you have a NaCl solution. Osmolarity is the same on both sides.

Urea isn’t in the cell, therefore it can move into the cell. Water can move freely. It is a hypotonic solution/situation