Animal Physiology Thursday, March 8th

Physiology, defined Physiology = study of fundamental biological tasks (digestion, circulation, structural support, movement, reproduction, etc), and how animals carry them out.

Overview For Today Levels of Organization Tissue Types Epithelial Tissue Connective Tissue Muscle Tissue Nervous Tissue Organs & Organ Systems

Levels of Organization The bodies of all living organisms follow a hierarchical organization that can include: Atoms Molecules Organelles Cells Tissues Organs Organ Systems

Tissue Types Epithelial Tissue Connective Tissue Muscle Tissue Nervous Tissue

Epithelial Tissue Tight sheet that lines the internal and external surfaces of the body (skin, digestive tract, body cavities) Selective barrier Can Be: Simple (single layer) Stratified (multiple cell layers) Pseudostratified (single layer that resembles stratified tissue)

Epithelial Tissue, Types Squamous – thin, flat plates; they form the lining of the mouth, blood vessels, heart, and outer layers of the skin Squamous cells have the appearance of thin, flat plates. The shape of the nucleus usually corresponds to the cell form and help to identify the type of epithelium. Squamous cells, for example, tend to have horizontall flattened, elliptical nuclei because of the thin flattened form of the cell. They form the lining of cavities such as the mouth, blood vessels, heart and lungs and make up the outer layers of the skin.

Epithelial Tissue, Types Stratified Squamous – for protection, skin & mouth

Epithelial Tissue, Types Cuboidal – cubes! Found in glands, lining of kidney tubules, & duct of glands. As their name implies, cuboidal cells are roughly square or cuboidal in shape. Each cell has a spherical nucleus in the centre. Cuboidal epithelium is found in glands and in the lining of the kidney tubules as well as in the ducts of the glands. They also constitute the germinal epithelium which produces the egg cells in the female ovary and the sperm cells in the male testes.

Epithelial Tissue, Types Columnar – columns! Elongated, long. Line the stomach & intestines Goblet Cells (unicellular glands) occur between the cells of duodenum; secrete mucus / slime to keep the surface smooth The nuclei are elongated and are usually located near the base of the cells. Columnar epithelium forms the lining of the stomach and intestines. Some columnar cells are specialized for sensory reception such as in the nose, ears and the taste buds of the tongue. Goblet cells (unicellular glands) are found between the columnar epithelial cells of the duodenum. They secrete mucus or slime, a lubricating substance which keeps the surface smooth.

Ciliated Columnar

Connective Tissue Supports, stabilizes, and protects the body’s main organs Ground Substance – proteins produced & secreted by cells, this fluid surrounds all connective tissue 5 Basic Types

Connective Tissue DENSE CONNECTIVE TISSUE Connects organs In tendons, around muscles, under skin

Connective Tissue LOOSE CONNECTIVE TISSUE Supports, insulates, nourishes organs Between organs and under skin

Connective Tissues BLOOD Transports oxygen, nutrients, wastes In the circulatory system (duh!)

Connective Tissue CARTILAGE Absorbs shock & friction In joints, ears, nose, trachea Connective Tissue

Tissue Types BONE Framework for body; muscle attachment In the skeletal system! (duh!)

Muscle Tissue Facilitates movement through the body by contracting Three basic Types

Muscle Tissue SKELETAL Function: Voluntary movement Attached to bones in the skeleton

Muscle Tissue SMOOTH Involuntary movement; assists digestion & circulation Found in digestive sys, veins, arteries

Muscle Tissue CARDIAC Involuntary movement, responsible for the heartbeat In the heart (duh!)

Nervous Tissue Produces and conducts electro-chemical signals between brain & body 4 Main Types

Nervous Tissue Types MOTOR NEURONS Send info from brain to muscles In spinal chord, brain, body

Nervous Tissues Types SENSORY NEURONS Send info from internal & external stimuli to brain In skin, ears, eyes

Nervous Tissue Types Association Neurons (aka Interneurons) They Integrate & relay info between neurons In spinal chord, brain

Nervous Tissue Types GLIAL CELLS (aka Neroglia) Structural support, facilitate info transfer along and between neurons Spinal Chord & Brain

Organs & Organ Systems Organs – composed of multiple tissues, carry out specific function Organ Systems – group of multiple organs working together

Organ Systems Skeletal – structural support, muscle attachment Made of bones, cartilage, ligaments

Organ Systems Muscular – movement! Made of Muscles!

Organ Systems Integumentary – protects body, regulates body temp Made of skin, sweat glands, nails, hair

Organ Systems Respiratory – facilitates oxygen intake, carbon dioxide removal Includes Lungs (or gills), trachea, skin

Organ Systems Circulatory – transports materials such as nutrients, waste products, carbon dioxide, oxygen Includes heart, blood vessels, blood

Organ Systems Digestive – breaks down food to get nutrients Includes mouth, stomach, intestines, liver, pancreas

Organ Systems Urinary – removes waste from blood Includes kidneys, bladder, ureters, urethra

Organ Systems Immune – defense against pathogens Includes white blood cells, lymph nodes, lymph vessels, spleen, thymus

Organ Systems Endocrine – controls & regulates bodily functions Includes glands

Organ Systems Reproductive – replicates genetic material, passed on to offspring Includes testes, ovaries, penis, uterus, vagina

Organ Systems Nervous – detects internal and external stimuli, aids in coordinating response Includes nerves, brain, spinal chord, sensory organs

Homeostasis To stay alive, animals need to maintain steady internal conditions Organ systems work together through homeostasis to do this Common regulation tool = negative feedback loop - the end product regulates the initial steps in the process

Negative Feedback Loop Blood Calcium Levels Low levels causes body to pull Ca from bones When levels are good again, this stops

Positive Feedback Loop Things keep building and building until a proper level is reached, then it’s shut off Ex: Childbirth & contractions