physiology day 1 notes: body systems, homeostasis, feedback systems

anatomy and physiology

2 branches of science that deal with body parts & functions

anatomy

science of body structures & relationships

first studies done by dissection

imaging techniques

physiology

science of body functions

structure and function of body

structure of a part of the body allows performance of certain functions

ex: bone of skull provides protection for the brain, thin air sacs of lungs permit movement of oxygen

6 main levels of structural organization

chemical, cellular, tissue, organ, system, organismal

chemical level

atoms: carbon, hydrogen, oxygen, nitrogen, phosphorus —> molecule DNA

cellular level

ex: smooth muscle cell

tissue level

ex: smooth muscle tissue

organ level

ex: stomach

system level

ex: digestive system

organismal system

ex: human

11 systems of human body

integumentary

skeletal

muscular

nervous

endocrine

cardiovascular

digestive

urinary

lymphatic

respiratory

reproductive

integumentary system components

skin and structures associated with it (hairs, nails, sweat glands, oil glands)

integumentary system functions

protects body

regulates body temperature

eliminates waste

helps makes vitamin D

detects sensations such as touch, pain, warmth, & cold

skeletal system components

bones and joins of the body and their associated cartilages

skeletal system functions

 supports & protects body

provides a surface areas for muscle attachments

aids body movements

houses cells that produce blood cells

store minerals and lipids (fats)

muscular system components

muscles composed of skeletal muscle tissue (which is usually attached to bones)

muscular system functions

produces body movements (ex: walking)

stabilizes body position (posture)

generates heat

nervous system components

brain, spinal cord, nerves, & special sense organs (ex: eyes, ears)

nervous system functions

generates action potentials (nerves impulses) to regulate boy activities

detects changes in the body’s internal and external environments

interprets changes and responses by causing muscular contractions or glandular secretions

electrical communication

endocrine system components

hormone-producing glands (pineal gland, hypothalamus, pituitary gland, thymus, thyroid gland, parathyroid glands, pancreas, ovaries, and testes) and hormone-producing cells in several other organs 

endocrine system functions

regulates body activities by releasing hormones, which are chemical messengers transported in blood from an endocrine gland or tissue to a target organ, hormones transported through blood & specific receptors for each chemical

cardiovascular system components

blood, heart, & blood vessels

cardiovascular system functions

heart pumps blood through blood vessels

blood carries oxygen and nutrients to cells and CO2 and wastes away from cells

helps regulate acid-base balance, temperature, and water content of body fluids

blood components help defend against disease & repair damaged blood vessels

digestive system components

organs of GI tract, a long tube that includes the mouthn, pharynx (throat), esophagus, stomach, small & large intestines, and anus

accessory organs that assist in digestive processes such as the salivary glands, liver, gallbladder, & pancreas

digestive system functions

achieves physical & chemical breakdown of food

absorbs nutrients

eliminates solid wastes

urinary system components

kidneys, ureters, urinary bladder, & uretha

urinary system functions

produces, stores, & eliminates urine

eliminates wastes & regulates volume and chemical composition of blood

helps maintain the acid-base balance of body fluids

maintains body’s mineral balance

lymphatic system functions

lymphatic fluid (lymph) and vessels; spleen, thymus, lymph nodes, & tonsils 

lymphatic system components

returns proteins and fluid to blood

carries lipids from gastrointestinal tract to blood

includes structures where lymphocytes that protect against disease-causing microbes mature and proliferate 

respiratory system components

lungs & air passageways such as the pharynx (throat), larynx (voice box), trachea (windpipe), and bronchial tubes leading into & out of lungs

reproductive system components

gonads produce gametes (sperm/oocytes) that unite to form a new organism

release hormones that regulate reproduction and other body processes

associated organ transport and store gametes

external environment

surrounding the body

internal environment

the environment in which the cells of the body actually live

types of body fluids

intracellular (ICF), extracellular (ECF)

types of ECFs

interstitial fluid, plasma

interstitial fluid (IF)

fluid outside the cells

plasma

fluid portion of blood

body’s internal environment

80% made of water

body cells in contact with water environment

internal environments are the fluid around the cells

materials that exchange between blood and tissue

nutrients, gases, wastes

process of material exchange

Blood —> External Fluid —> Tissue Cells

1. blood travels through tiny blood vessels (capillaries)

2. the plasma (liquid part of the blood) carries nutrients, oxygen, & other materials

3. the fluid surrounding the tissue cells is called external fluid

4. materials pass through this fluid to get between the blood & cells

5. nutrients & oxygen move from the blood —> external fluid —> tissue cells

6. cells use these materials to function

7. tissue cells produce waste (ex: CO2)

8. waste moves from the tissue cells —> external fluid —> to blood

9. blood carries the waste away so the body can get rid of it

homeostasis

maintenance of a stable, relatively constant, internal environment (an internal equilibrium)

controlled conditions in an internal environment

temperature, pH, concentration of glucose, ions, gases

homeostatic range

pre-set limits of these controlled variables

dynamic condition

always responding to environmental conditions

every cell/organ/system in the body contributes to homeostasis

homeostasis as a dynamic condition (external & internal)

external: blood temperature

• too hot: sweat

• too cold: shiver

internal: concentration of blood glucose

too high: release insulin

too low: release glucagon

3 components of homeostatic control feedback system

receptor: sensory neuron

control center: brain

effector: muscle gland

receptor

body structure that monitors changes in a controlled condition, sends an input to the control center (brain)

types of receptors

thermoreceptors (in the skin): for temperature

baroreceptors (in blood vessel wall): for pressure

chemoreceptors (in blood vessel wall): for different levels of atoms/chemicals

osmoreceptors (in hypothalamus): detects changes in osmosis/water diffusion

control center

brain

brain function in feedback systems

sets range of values that need to be maintained (depends on DNA)

evaluates input received from receptors & generates output command

output command is mediated by nerve impulses and/or hormones

effector

muscle gland

muscle gland role in feedback systems

receives output from control center

produces a response/effect that changes the controlled condition

negative feedback systems

opposes a change in the original stimulus

returns to homeostatic conditions

body typically operates on negative feedback system

ex: blood sugar regulation, blood pressure regulation

positive feedback loop

amplifies original stimulus

ex: cut, needs to start sending signals for blood clotting, increases blood clotting to stop bleeding

ex: childbirth, contractions → more oxytocin → stronger contractions → more oxytocin (oxytocin causes uterus to contract)

baroreceptor reflex

regulation of blood pressure, negative feedback loop

blood pressure

force exerted by blood as it presses against the walls of the blood vessels

receptors in regulation of blood pressure

baroreceptors (pressure sensitive)

control center in regulation of blood pressure

cardiovascular (CV) system of the brain

effectors in regulation of blood pressure

heart & blood vessels

baroreceptor reflex process in regulation of blood pressure

stimulus causes a decrease in BP

baroreceptors - detect drop in BP

sends a message (neurons) to the control center (CV center of brain)

sends a message (neurons) to the effectors

heart = increases force & rate of heart contraction

blood vessels = vasoconstriction (get smaller, reduce blood flow, and increase pressure)

result: BP increased to homeostatic levels

• process also works to decrease BP