ANSC 201: General Physiology - Exam 1

General physiology

Animal functions are mostly based on people’s observations and theories

Body organization

Cells => Tissues => Organs => Systems => Whole Body

Thoracic cavity - spinal cord, soft organs called viscera, and surrounding body wall

Thoracic cavity (upper) - heart and lungs

Layer of muscle (diaphragm) separates the thoracic and abdominal cavity

Abdominal cavity (lower) - digestive organs

Directional terms

Dorsal - along spinal column

Ventral - opposite side of dorsal

Posterior - back end

Caudal - area around animal’s tail

Anterior - front end

Cranial - skull or head

Proximal - anything close to a given/defined point

Distal - anything far away from a given/defined point

Environments (mammals)

External - gaseous

Internal - fluid-filled/aqueous

Fluid filled spaces

Intracellular - within cells (45% BW)

Interstitial - between cells (17% BW)

Circulatory - blood plasma (6% BW)

Added together, these make up 68% BW (body is 2/3 water)

Equilibrium changes affect fluid balances

Homeostasis

Keeps the animal’s internal environment constant

Homeostasis Primary Systems

Circulatory - permit exchange of nutrients, hormones, and gases, etc

Respiratory

Urinary

Digestive

Skeletal

Muscular

Nervous System

Endocrine System

Nervous System

Makes adjustments to maintain equilibrium

Receptors - detect changes in the environment

External - eyes, ears, etc

Internal - detect changes in blood, etc

Peripheral Nervous System

Autonomic - control involuntary muscle; sympathetic - emergency; parasympathetic - at rest

Somatic - control skeletal muscle

Previous experience (conditioned reflex) - after repeated exposure, reaction may weaken or strengthen

General rule* - when a change in environment, usually external environment, requires a rapid response or the whole body, it is the nervous system

General rule* for nervous system and endocrine system

Nervous - fast or whole body response; response to outside change in environment

Endocrine - long term or specifc reponse; response to inside change in environment

Endocrine System

Secretes organic substances to be exchanged by circulatory system

Exocrine - exiting the gland or body; no blood; mammary gland

Endocrine - secreting; picked up by bloodstream

Pancreas has both an exocrine function (eg digestive enzymes) and endocrine function (eg insulin)

General rule - when a change in environment, usually internal, requires a specific response for altering cell environment or a longer-term response, its usually the endocrine system

Hormones

A chemical substance secreted by a ductless gland

Protein - made from amino acid chains (eg insulin and somatropin)

Amino-acid derived - made from individual amino acids (eg melatonin from tryptophan or epinephrine from tyrosine)

Steroids (or lipid-based) - derivatives of cholesterol; many reproductive hormones (eg estrogen and testosterone)

Controlling their release - nervous system, other hormones, change in chemical composition of blood

*Some hormones target the entire body while others target specific areas

Negative Feedback Mechanism

Central nervous system => hypothalamus => anterior pituitary => another endocrine gland => target organ or tissue

Action of hormones

Excite vs inhibit

Change enzyme synthesis rates

Increase cell membrane permeability

Independent - no interaction

Antagonistic - equal and opposite effects

Complementary- work together

What do I need to know (for exam 2)

Specific hormones and their names, site of production or release, target organ(s), and function