Anatomy test

Negative feedback

The response counteracts or reverses the initial change to bring the body back to equilibrium.

Goal of Negative feedback

Stability — to keep conditions within a normal range (set point).

Example of Negative feedback

Body Temperature Regulation:

• Stimulus: Body temperature rises.

• Receptors: Skin and hypothalamus detect change.

• Control Center: Hypothalamus triggers response.

• Effectors: Sweat glands activate → body cools → temperature returns to normal.

Homeostasis 

the process by which the body maintains a stable internal environment despite external changes (e.g., maintaining body temperature, blood sugar, or pH).

Positive feedback

The response amplifies or enhances the original stimulus.

Goal of positive feedback

Drives a process to completion rather than maintaining balance.

Exampel of postive feedback

Childbirth: Stretching of the uterus triggers oxytocin release, which increases contractions — leading to more stretching until the baby is delivered.

Stimulus

The change in environment that disrupts balance

Example of Stimulus

Heat increases body temperature

Receptor (sensor)

Detects the change and sends information to the control center

Example of receptor

Skin nerve endings detect heat

Control Center

Processes the information and determines the proper response

Example of Control Center

Hypothalamus in the brain

Effector

Carries out the command from the control center

Example of Effector

Sweat glands, blood vessels

Response 

The result that restores balance

Example of Response

Sweating and vasodilation lower temperature

Main function of Epithelial tissues

Protection, absorption, secretion, filtration

Location of Epithelial Tissues

Covers body surfaces, lines organs, forms glands

Characteristics of Epithelial tissues

Closely packed cells with minimal matrix; avascular (no blood supply); regenerate quickly

Main Function of Connective tissues

Support, binding, protection, transport

Location Connective Tissues

Found everywhere (bone, fat, blood)

Charcteristics of Connective Tissues

Cells scattered within a non-living extracellular matrix

Function of Muscle

Movement (internal and external)

Location of Muscle Tissue

Skeletal muscles, heart, walls of organs

Charcteristcs of Muscle Tissue

Contractile tissue; elongated cells with actin and myosin filaments

Function of Nervous Tissues

Communication and control

Location of Nervous Tissues

Brain, spinal cord, nerves

Characteristics of Nervous Tissue

Neurons transmit signals; neuroglia support neurons

Simple

one layer (for absorption, secretion, diffusion)

Stratified

multiple layers (for protection)

Pseudostratified

looks multilayered but is one layer with nuclei at different levels

Squamous

flat, thin cells (for diffusion)

Cuboidal

cube-like cells (for secretion/absorption)

Columnar

tall, rectangular cells (for absorption/secretion)

Structure of Simple Squamous

Single, thin layer of flat cells

Location of SImple Squamous

Lungs (alveoli), capillaries

Function of Simple Squamous

Allows diffusion and filtration

Structure of Simple Cuboidal

Single layer of cube-shaped cells

Location of Simple Cuboidal

Kidney tubules, glands

Function of Simple Cuboidal

Secretion and absorption

Structure of Simple Columnar

Single layer of tall cells (may have microvilli/goblet cells)

Location of Simple Columnar

Digestive tract lining

Function of Simple Columnar

Absorption and mucus secretion

Structure of Pseudostratified Columnar

Appears layered but is not; often ciliated

Location of Pseudostratified Columnar

Trachea, respiratory tract

Function of Pseudostratified Columnar

Moves mucus; protects airways

Structure of Stratified Squamous

Many layers; outer cells flat and dead (keratinized)

Location of Stratified Squamous

Skin, mouth, esophagus

Function of Stratified Squamous

Protection from abrasion

Structure of Transitional Epithelium

Layers of rounded cells that stretch

Location of Transitional Epithelium

Urinary bladder

Function of Transitional Epithelium

Stretching and recoil for urine storage

Cilia 

Hair-like extensions that move substances along surfaces (e.g., move mucus in respiratory tract).

Microvilli

Finger-like projections that increase surface area for absorption (e.g., intestines)

Goblet Cells

• Specialized epithelial cells that secrete mucus to protect and lubricate.

Apical Surface

Exposed to the body’s exterior or to an open space inside an organ (lumen).

Basal Surface

Attached to the basement membrane; anchors cells to connective tissue.

Basement Membrane

A thin layer of proteins and fibers that connects epithelial tissue to underlying connective tissue and provides structural support.

Exocrine Glands

• Have ducts that secrete substances onto surfaces or into cavities.

• Examples: Sweat glands, salivary glands, oil glands.

Endocrine Glands 

• Ductless glands that secrete hormones directly into the bloodstream.

• Examples: Thyroid, pancreas (insulin production).

Cells in Connective Tissue

Specialized cells like fibroblasts, chondrocytes, osteocytes, blood cells

Function of Cells in Connective Tissues

Create and maintain matrix

Collagen Fibers in Connective Tissues

Thick, strong, non-elastic fibers

Function of Collagen Fibers in Connective Tissues

Provide tensile strength

Elastic Fibers in Connective Tissues

Thin, stretchy fibers made of elastin

Function fo Elastic Fibers in Connective Tissues

Provide flexibility and resilience

Reticular Fibers in Connective Tissues

Fine, branching collagen fibers

Function of Reticular Fibers in Connective Fibers 

Form supportive frameworks

Ground Substance in Connective Tissues

Gel-like material filling space between fibers

Function of Ground Substance

Supports cells, stores nutrients, allows diffusion

Areolar Function

Cushions organs, holds tissues together

Areolar Structure

Loose fibers, open space

Location of Areolar 

Beneath epithelium, around blood vessels

Adipose Function

Stores fat, insulates, protects

Adipose Structure

Densely packed fat cells

Location of Adipose

Under skin, around kidneys, heart

Dense Regular Function

Resists tension in one direction

Dense Regular Structure

Collagen fibers arranged in parallel

Dense Regular Location

Tendons, ligaments

Hyaline Cartilage Function

Smooth surface for movement

Hyaline Cartilage Structure

Glassy matrix with chondrocytes

Hyaline Cartilage Location

Ends of bones, trachea, nose

Bone (Osseous) Function

Structure, protection, mineral storage

Bone (Osseous) Structure

Rigid matrix with calcium and collagen

Bone (Osseous) Location

Skeleton

Blood Function

Transports oxygen, nutrients, waste

Blood Structure

Plasma matrix with red and white cells

Blood Location

Within blood vessels

Tendons

Connect muscle to bone

Ligaments 

Connect bone to bone.

Ligaments and tendons are made up of

Dense regular connective tissue — packed with strong collagen fibers arranged in parallel for strength

Hyaline Cartilage Location

Nose, trachea, ends of long bones

Hyaline Cartilage Function

Flexibility and smooth surface

Hyaline Cartilage Special Trait

Glassy appearance

Elastic Cartilage Location

Ear, epiglottis

Elastic Cartilage Function

Flexibility with shape retention

Elastic Cartilage Special Trait

Contains elastic fibers

Fibrocartilage Location

Intervertebral discs, pubic symphysis

Fibrocartilage Function

Absorbs Shock