hhp 101 - tissues and stuff

What are the four general types of tissue?

Epithelial, Connective, Muscle, Nervous.

What is the main function of epithelial tissue?

Covers structures, lines organs and body cavities, and forms barriers.

What is the basement membrane (basal lamina)?

A type of extracellular matrix on which epithelial cells rest, helping anchor them.

What is the difference between simple and stratified epithelium?

Simple: one cell layer; Stratified: multiple cell layers.

Why is the epidermis made of stratified squamous epithelium?

Multiple cell layers provide thickness and protection.

Why is the small intestine lined with simple columnar epithelium?

A single cell layer supports nutrient absorption.

What are microvilli?

Folds of the plasma membrane that increase surface area for absorption.

What functions can epithelial tissue perform?

Diffusion, Osmosis, Filtration, Secretion, Ion absorption, Protection.

What is membranous epithelium?

Epithelium that forms sheets covering surfaces or lining cavities.

What functions are associated with simple epithelium?

Diffusion, osmosis, filtration, and absorption.

What function is especially associated with stratified epithelium?

Protection.

What is glandular epithelium?

Epithelium specialized for producing and releasing substances.

What is the difference between exocrine and endocrine glands?

Exocrine: release fluids through ducts; Endocrine: produce hormones that enter the blood.

Give an example of an exocrine gland.

Sweat gland.

How does epithelial structure illustrate "form follows function"?

The number of cell layers and features such as microvilli suit the tissue to its function.

What is the primary function of connective tissue?

Binds cells and organs together and connects structures.

What are the three components of connective tissue listed in the lecture?

Cells, Ground substance, Protein fibers: collagen, reticular, and/or elastic.

What are the two broad categories of connective tissue?

Connective tissue proper, Specialized connective tissue.

What are the two types of connective tissue proper?

Dense connective tissue, Loose connective tissue.

What are the specialized connective tissues?

Blood, Bone, Cartilage.

What is the function of fibroblasts?

Synthesize and secrete extracellular matrix and collagen.

What is the function of macrophages?

Engulf microorganisms and help protect against bacteria and viruses.

What connects muscle to bone?

Tendons.

What connects bone to bone?

Ligaments.

Where is loose connective tissue found, according to the lecture?

Holds contractile muscle fibers together; surrounds blood vessels.

What is adipose tissue?

A modified type of loose connective tissue in which fat cells accumulate in large numbers.

What are the two types of adipose tissue?

White adipose tissue, Brown adipose tissue.

What are three functions of adipose tissue?

Energy storage, Thermal insulation, Cell signaling.

What are adipocytes?

Fat cells.

What are adipokines?

Cell-signaling molecules released by fat cells.

Why do cartilage injuries heal slowly?

Cartilage has a thick extracellular matrix and no blood supply penetrating it.

What are the three types of cartilage and their locations?

Hyaline cartilage: most common; found at the ends of bones. Elastic cartilage: flexible; found in the ears. Fibrocartilage: found in the outer rings of intervertebral discs.

What are two major functions of bone?

Internal structural support, Protection of organs.

How does bone contribute to homeostasis?

Helps maintain blood calcium (Ca²⁺) levels.

What are compact and spongy bone?

Two forms of bone tissue.

What are the formed elements of blood?

Red blood cells, White blood cells, Platelets.

What is the extracellular matrix of blood?

Plasma, which accounts for approximately 55% of blood volume.

What are the three types of muscle tissue?

Skeletal muscle, Cardiac muscle, Smooth muscle.

What are the characteristics of skeletal muscle?

Multinucleated, Striated (striped), Long, cylindrical cells called fibers, Cells cannot divide, Voluntary force.

What are the characteristics of cardiac muscle?

Usually a single nucleus, Striated, Branched and connected cells, Involuntary force.

What are the characteristics of smooth muscle?

No striations, Usually forms bands or sheets, Involuntary force.

What connects muscle to bone?

Tendons.

What is the epimysium?

Connective tissue surrounding the entire muscle.

What is a fascicle?

A bundle of muscle fibers.

What is the perimysium?

Connective tissue surrounding and bundling muscle fibers into fascicles.

What is a muscle fiber?

A single muscle cell.

What is the endomysium?

Connective tissue surrounding an individual muscle fiber.

What is the endocardium?

The inner endothelial lining of the heart.

What is the myocardium?

The muscular part of the heart wall, consisting mostly of muscle cells and collagen.

What is the pericardium?

The double-walled sac surrounding the heart that contains fluid.

What is the sarcolemma?

The muscle cell membrane.

What is the sarcoplasmic reticulum (SR)?

A specialized form of endoplasmic reticulum in muscle cells.

What are myofibrils?

Structures within muscle fibers that produce force, made of repeating units called sarcomeres.

What is a sarcomere?

A repeating structural unit of a myofibril that can shorten to produce muscle force.

What activates muscle contraction, according to the lecture?

Calcium ions (Ca²⁺).

What is the primary role of myosin?

Generates force and motion using ATP.

What is the primary role of actin?

The thin-filament protein that myosin pulls on during contraction.

What does troponin do?

Binds Ca²⁺.

What does tropomyosin do?

Blocks myosin-binding sites on actin when contraction is not activated.

What does titin do?

Functions as a giant elastic protein in the sarcomere.

What makes up the thin filament?

Actin, Troponin, Tropomyosin.

What makes up the thick filament?

Mostly myosin.

What is the Z-disk?

A sarcomere structure containing alpha-actinin and approximately 30 other associated proteins.

What is an ATPase?

A protein or enzyme that uses ATP to perform molecular tasks.

What is the myosin crossbridge cycle?

The ATP-dependent process through which myosin couples ATP breakdown to mechanical movement and force generation.

What happens to sarcomeres during contraction?

They shorten.

Which muscle types have sarcomeres, according to the lecture?

Skeletal muscle, Cardiac muscle.

What is cardiomyopathy?

A disease of the heart muscle that can impair its ability to pump blood.

What is heart failure?

The inability of the heart to produce sufficient power to pump blood effectively.

What is ejection fraction?

The percentage of blood pumped out of the left ventricle.

What is systole?

The phase when the heart pumps blood.

What is diastole?

The phase when the heart relaxes to fill with blood.

What is HFrEF?

Heart failure with reduced ejection fraction.

What is HFpEF?

Heart failure with preserved ejection fraction.

What is hypertrophic cardiomyopathy (HCM)?

A genetic heart disease characterized by abnormal thickening of the heart muscle.

How can a sarcomere protein mutation cause hypertrophic cardiomyopathy?

A missense mutation can affect a sarcomere protein and cause excessive force production and heart-wall thickening can develop over decades.

Why is hypertrophic cardiomyopathy important in young athletes?

It is a common cause of sudden cardiac death in young athletes.

What is Mavacamten (Camzyos)?

An FDA-approved cardiac myosin inhibitor used for hypertrophic cardiomyopathy that turns myosin off.

What is muscular dystrophy?

A degenerative skeletal muscle disease associated with progressive muscle dysfunction or weakness.

What causes Duchenne muscular dystrophy (DMD)?

Absent or nonfunctional dystrophin.

What is the function of dystrophin?

Links the muscle cytoskeleton to the sarcolemma and helps maintain structural integrity of muscle.

What are myotropes?

Drugs that target sarcomere proteins to modify muscle force.

What is Sevasemten?

A skeletal myosin inhibitor described in Phase 3 clinical trials for Becker muscular dystrophy.

What is Danicamtiv?

A sarcomere activator that binds cardiac myosin and increases myosin affinity for actin; described in Phase 2 research.

What is Reldesemtiv?

A skeletal troponin activator that increases troponin sensitivity to Ca²⁺; trials were discontinued.

What is the difference between Mavacamten and Sevasemten?

Mavacamten: cardiac myosin inhibitor for hypertrophic cardiomyopathy; Sevasemten: skeletal myosin inhibitor for Becker muscular dystrophy.

What is the CNS composed of

brain and spinal cord

what is the PNS composed of

cranial and spinal nerves

What is the role of nervous tissues

communicate with internal and external environment

Glial cells vs neurons

neurons are conducting, glia are non conducting

Neuroglial cells overview

do not conduct electricity

support neurons

maintain homeostasis

Cell body

nucleus and cytoplasm

dendrite

external appendages, trasnmit impulses towards cell body

axon

large process, transmit impulse away from cell body

axon terminal

end of axon, communication link to other cells

myelin sheath

• produced by schwann cells

• protective layer

• primarily lipid

• increases speed of nerve impulses

Nodes of Ranvier

small unmyelinated axon segments between myelin

Neruons ___ and ___ electrical impulses

generate, receive

dendrites __ information

receive

Nerve cells do not…

… divide and are difficult to regenerate. also sensitive to O2 level in blood