Tissue Level

What are Tissues?

A group of cells that have a similar structure and function together as a unit

What is Histology?

The study of microscopic structure of tissues

What are the four major connective tissues?

  1. Epithelial

  2. Connective

  3. Muscular

  4. Nervous

Where are Epithelial Cells found?

On the surface, Inner and outer surface of organs EX. 1. Most Glands

How are each tissues different from each other?

  1. Epithelial- act as coverings

  2. Connective- Binds various body parts together

  3. Muscular- Allows the body to move

  4. Nervous- Functions in communication

What is Matrix?

Extracellular material outside the cells made of fibers (Proteins)

Epithelial Tissue

What does Epithelial tissue include?

Epithelial Cells have 6 types of cells and two special ones

What are the four main functions of Epithelial cells?

  1. Secretion

  2. Protections

  3. Absorbtion

  4. transportation

  5. Special Sensory Receptive

What are the three main shapes of epithelial cells

  1. Squamous

  2. Cuboidal

  3. Columnar

How is epithelia further divided based on the number of cell layers

There are Simple epithelia which are one layer of cells, Then there are Stratified Epithelia which are multiple layers

Examples of Epithelia are….

Simple squamous epithelium: endothelium lining blood vessels and heart
Stratified squamous epithelium: surface of skin, tongue and esophagus, etc.
Simple cuboidal epithelium: glands, ducts
Stratified cuboidal epithelium: lining of some ducts
Simple columnar epithelium: lining of stomach, intestine
Stratified columnar epithelium: small areas of the pharynx and mammary gland
Pseudostratified ciliated columnar epithelium: Lining of nasal cavity, trachea

What are Keratinized and Non-Keratinized stratified Squamous Epithelium? Where are they Located?

Keratinized Squamous Epithelia are dead cells produced by Keratin (top layer of Epidermis)

Non-Keratinized Squamous Epithelia are just pure living cells found on the tongue, esophagus, and Vagina

What Is transition Epithelium?

It is a stratified epithelium that can withstand repeated cycles of stretching and recoiling. It is called transitional because it changes appearance as stretching occurs. It can look plump and cuboidal
to flat. (found in urinary Bladder and Ureter)

What are endocrine glands

Makes hormones but does not secrete them but releases them into the blood EX. Thyroid, Adrenal, Pituary

What are Exocrine Glands

Secretes substance through duct EX. Sweat Glands, Mammary Glands

Connective Tissue

What are the Main Functions of Connective tissue?

  1. Supporting organs and cells

  2. transports nutrients and waste

  3. defending against pathogens

  4. storing fat

  5. repairing damaged tissue

What are the Three Main types of Connective tissue?

  1. Fibrous Connective tissue

  2. Fluid Connective Tissue

  3. Supporting Connective Tissue

Functions of Connective cells

Fibroblasts- Produce fibers

Macrophages- ingest and degrade dead cells, and foreign material

Adipocytes- Provide energy storage, insulation from extreme heat and cushioning around organs

Mesenchymal Cells- making and repairing skeletal tissues, such as cartilage, bone and the fat found in bone marrow.

Mast Cells- Produces histamine (chemical involved in allergic reactions)

Lymphocytes- antibody protection

Plasma Cells- Produce antibodies(proteins)

What is Adipose Tissue?

Also known as body fat, connective tissue that extends throughout the body

What are examples of Loose C.T

  1. Areolar

  2. Adipose

  3. Reticular

Where is reticular C.T Located?

  1. Liver

  2. Spleen

  3. Lymph Nodes

What is the Function of Reticular Tissue?

Provides Supporting Framework

What is Dense C.T

Fibers that are packed very densely

What type of fibers are found in Dense C.T

Collagen

What are examples o dense C.T?

tendons are dense regular

deep dermis is irregular dense

Functions of Loose and Dense and C.T

Loose holds organs, anatomic structures, and keeps tissues in place

Dense transmit forces over distance and to connect different organs/muscles

What does Fluid connective tissue do?

Transports Fluid, nutrients, waste, and chemical messenger

What are two types of connective tissue? What are their Main functions

  1. Cartilage- Reduces friction between joints

  2. Bone- provides structural support to the body

What are Chondrocytes?

cells that make up cartilage

What are Osteocytes?

Cells that makes up bones

What are the four types of Membrane? And Location?

  1. Cutaneous- The skin

  2. Mucous- digestive tract, respatory, urinary, reproductive

  3. serous- heart, lung, abdominal organs

  4. Synovial- joint cavities

Muscle Tissue

What are the Three Main types of Muscle Tissue?

  1. Skeletal- responsible for body movement

  2. Cardiac-responsible for blood circulation

  3. Smooth- contractility and support for certain organs

What are voluntary and involuntary striation Muscles?

Voluntary means you move the muscle conciously

Involuntary means the body part moves on its own

What are striated and Non-striated muscles?

striated are long cells and and non-striated are spindle shaped

Nervous tissue

What are the two main cells of nervous tissue?

  1. Neuroglia(most common

  2. Neurons

Function of each cell type?

Neuroglia protects and supports Neurons

Neurons transmits information

What is an axon and its function?

Big branch of a Neuron that sends out signals

What are dendrites and its function?

Small embranching branches that receive signals from other cells


Integumentary System

What does the Integumentary System Include?

The Skin

What are the Functions of the Skin?

  1. Protects Underlying tissue and organs

  2. Excretes salts, water, and organic waste through glands

  3. Maintains Body temp

  4. synthesizes Vitamin D

  5. Stores Lipids

  6. Has a lot of receptors

How many Layers does the Skin Have and what are they?

It has two layers

  • Epidermis(top Layer)- made of Keratinized stratified Squamous Epithelia

  • Dermis- Made of connective tissue

What can you find in The epidermis?

  • Keratinocytes

  • Melanocytes

  • stem cells

  • Dendritic cells

What are the Layers of the Epidermis Top to Bottom?

  1. (Top)Stratum Corneum- Made of a lot of dead cells

  2. Stratum Lueidum-Cells are dead (palm and soles)

  3. Stratum Granulosom- cells where they are about to die

  4. Stratum Spinosum- Can contain up to 40 cells and dendritic cells

  5. Stratum Basale- contains 10 cells and the stem cell

What Layer is not present in Thin Skin?

The Stratum Lucidum

Which Layer has Blood Vessel?

The Dermis

What do you find in the Dermis?

  • Has a lot of Matrix

  • papillary layer-made of Loose CT

  • Reticular layer-irregular dense CT

What is the Hypodermis? What does it include and it function

  • Not part of the skin

  • full of adipose tissue

  • provides thermal insulation

Classifications of burns

1st degree burn- a bit through the epidermis

2nd degree burn-through the epidermis and a bit through the dermis(painful because of nerve irritation)

3rd degree burn-all the skin is gone(skin graft needed)


The Skeletal System


What is the Skeletal system composed of?

  • Bones

  • Cartilage

  • ligaments

  • tendons

What are the three types of Cartilage?

  1. Hyaline (most common found in joints, respiratory tract)

  2. Elastic-has a lot of elastic fibers and tolerates distortion with no damage(found in ears, larynx)

  3. Fibrocartilage-is very tough, resists compression(found between pubic bone, between vertebrae)

What are the Main functions of the Skeletal system

  • Provides support throughout the entire body

  • Store calcium salts and store energy reserves in the form of lipids in yellow marrow; blood cells are produced in the red marrow

  • Protect soft tissue and organs

  • acid base balance

Where are Blood cells produced?

Blood formation

Bone shapes

  • Long- When the Length is greater than the width (fingers, femur)

  • Short- Equal in length and width (carpal, tarsals)

  • Flat Bones- has a big surface are for muscles to attach (Sternum, ribs)

  • Irregular Bone- shapes that don’t fit into other categories (Vertabrae, Sphenoid, Ethmoid

What is Bone matrix composed of?

Crystals of hydroxyapatite and collagen.
Hydroxyapatite is formed by interaction of calcium phosphate with calcium
hydroxide. Collagen mixed with crystals of hydroxyapatite, a protein-crystal
combination, gives bone its strength and flexibility.

Bone is mainly made of bone matrix
and roughly 2/3 of bone mass is accounted for by calcium and roughly 1/3 is contributed
by collagen and 2% are osteocytes

What are osteocytes, osteoblasts, osteoprogenitor cells, and osteoclasts? Where do
you find each type of bone cells?

  1. Osteocytes- bone cells

  2. Osteoblasts-building cells (immature)

  3. Osteoprogenitor- stem cells of bone cells

  4. Osteoclasts- WBC’s dissolving cells

What is the difference between osteogenesis and osteolysis?

  • Osteogenesis- New Bone formation

  • Osteolysis-Condition where bone tissue is constantly destroyed

Rate of osteogenesis is greater than osteolysis then the bone gets stronger


Compact Bone- Dense, looks smooth and homogenous

Spongy Bone- has a spiky, open appearance that looks like a sponge


What is an Osteon What is a trabeculae

Basic Unit of compact bone Basic unit of Spongy bone

Structure of an osteon

Compact bone is located in parts of the body where stresses are generally stronger but
limited in direction. Like the thigh bone (femur) can tolerate 10-15 times of your body
weight but can easily break if pressure is applied from the sides. Spongy bone can tolerate
weaker stresses from multiple directions. Like the head of the thigh bone can tolerate
pressure from several directions without breaking.


Ossifiction

  • also called as bone formation

  • a process where most bones are develop using hyaline cartilage structures as their “models.”

Intermembranous Ossification

  • Produces the flat bone of the skull and most of the clavicle

  • Often referred as the dermal ossification because it takes place in the dermis

Enchondrial Ossification

  • refers to the conversion of pre-existing cartilage into bone.

  • increases length of bone

How is bone mass affected by exercise, Hormones and vitamins?

  • Stimulates Osteoblasts

  • Vitamins like A, B12, K, C

  • Hormones like Estrogen and androgens stimulate osteoblasts

Parathyroid Hormone (PTH)

  • Secreted from the parathyroid Gland into the blood

  • increases blood calcium levels

  • targets the Small intestine to absorb more calcium

  • Targets the Bones to release calcium ion reserves

  • Targets Kidneys to not excrete calcium

Calcitonin Hormone

  • Reduces Blood calcium leveles

  • produced by the thyroid gland

  • Targets the small intestine to not absorb more calcium

  • Targets the bones to tell osteoclasts to stop destroying bone and tells osteoblasts to increase its activity

  • Targets kidneys to excrete calcium through urine

Osteoperosis

Is a condition where bones become fragile and are likely to break
under stresses that younger individuals can easily tolerate

Osteopenia

reduced boned mass lesser severity than Osteoperosis


As a percentage of the total amount in our bodies, how much calcium is found in the
bones? Answer: 99% Therefore bones contain 99% of the total calcium in our bodies.