Cells

Homeostasis

the relative stability of the body’s internal conditions

• tendency of organisms to maintain relatively stable internal environments despite changes in external conditions, diet, or activity level

Parameters

must remain constant for our molecules and cells to be able to survive and perform their functions

• pH is a parameter

  • Stomach pH changes

Negative feedback

a biological response in which the effects of a reaction. slow or stop that reaction

• deviation from set point (sensed and detected by brain) → then responds to stimulus by turning off the effectors to try and go back to normal

• example: if body temperature is too high, the person begins to sweat and blood vessels dilate (widen), increasing blood flow to the skin.

  • Increases the amount of heat lost to the surroundings (surface area)

• example: if body temperature is too low, the person begins to shiver so that their muscle will generate more heat through cellular respiration

  • blood vessels also constrict, decreasing blood flow to the skin which limits heat loss

Effector

an organ or cell that acts in response to a stimulus

• swear glands to produce sweat when its too hot

Sensor

a structure that detects in the internal or external environment of an organism

• nerve cells in skin and brain

• negative feedback effectors “turn off” the action of the sensor

Homeostatic regulation

• involve behaviors to stay near or return to a set point

• If a person gets too hot, they may feel like lying down without moving, minimizing heat production

• If a person gets too cold, they might feel like moving around

Positive feedback

change in a bodily condition triggers a response that moves the body further away from its normal state until a specific endpoint is reached

• cascade/snowball effect

• intensifies until there is an intteruption

• example: contractions when pushing baby → heat pushes against cervix → nerves send signals to brain → releases oxytocin which relaxes uterus → pushes more

Regional anatomy

the study of the body’s structure by region, such as the head, abdomen, or arm, and how the structures in that region relate to each other

• ex: abdomen

(what we focus on for lab)

Systemic anatomy

the study of the human body’s structure by examining the body’s systems, or groups of structures that work together to perform a specific function

ex: cardiovascular system

Organ systems

organs that work together toward one or a set of functions

cell membrane

transport, shape, gateway to cell

cytoplasm

chemical storage, enzyme catalysts

nucleus

DNA and RNA

ribosomes

protein synthesis, reads mRNA

centrosomes

structure that divides cells

Mitochondria

Powerhouse of the cell ;)

endoplasmic reticulum

modifies proteins

glogi appartus

prepares proteins and lipids

lysosomes

break down different components

purpose of cell membrane

gives cell shape, resists outward pressure from other cells, made of lipids (fat)

selectively permeable

proteins allow for active transport, lipid bilayer allows diffusion

cell signaling

allows for hormonal communication, contains receptors on surface

cell recognition

contains structures that allow cells to recognize each other

Diffusion

solute moves from area of high concentration to low concentration until an equal distribution is reached

• necessary for things like transportation of O2 from lungs to blood

Osmosis

movement of water through a special barrier into an area of high concentration of dissolved stuff

hypertonic

more solute outside cell

• water moves toward solute → cell inside shrinks)

hypotonic

more solute inside

• water move inside → swells up

Isotonic

balanced amount of solutes in and out of cell

why does the water move?

because of chance → water constantly moves randomly (no energy needed)

• when solute interacts with water, it makes water on the solute side less likely to escape back the membrane

• WATER MOVES IN BOTH DIRECTIONS

Channel protein

molecules can only move from areas of higher concentration to areas of lower concentration through the channel

Carrier mediated

variation of diffusion where protein channels assist with transport across membrane

• highly specific due to binding mechanisms

Carrier protein

an ion or molecule will bind to the carrier protein, triggering a change in the protein’s shape such that he ion or molecule can pass