Hesi A2 anatomy

from smallest to largest, what are the levels of organization in the human body

cells

tissues

organs

organ systems

human body

what is the thoracic cavity and organs does it contain

it is the sternum and ribs. It contains organs such as the lungs, heart, trachea, esophagus, and bronchial tubes

what is the abdominal cavity and what organs does it contain

it is separated from the thoracic cavity by the diaphragm. contains:

stomach

gallbladder

liver

smaller intestines

large intestines

these organs are held by a membrane called the peritoneum

what is the pelvic cavity and what organs does it contain

it is enclosed by the pelvis, or bones of the hip. contains:

urinary bladder

uretha

ureters

anus

rectum

reproductive organs

besides thoracic, abdominal, and pelvic, what are the other two body cavities?

spinal cavity

cranial cavity

what is the anatomic position?

body is straight up and the hands are pointed forward, and palms are facing out the

why is sodium bicarbonate released into the lumen of the small intestine

sodium bicarbonate neutralize stomach acid and protect digestion because sodium bicarbonate is a base that neutralizes chyme, which is very acidic. Without sodium bicarbonate, the walls of the small intestine will be damaged and may form ulcers

using anatomic terms, how is the elbow positioned relative to the wrist

the elbow is proximal to the wrist, which means it is close to the attachment point

when considering the head and neck, which structure is superior, inferior, and what are the alternative names for these relationships?

The head is superior to the neck, the terms cephalic or cranial may be used in place or superior

The neck is inferior to the head, the term caudal may be used in place of inferior

using anatomic terms, how are the eyes positioned relative to the nose

the eyes are lateral to the nose

what are the three main planes of the body and how are they described

frontal plane: a vertical plane that divides the body or organ into anterior and posterior

sagittal plane: vertical plane that divides the body or organ into right and left sides

transverse plane: a horizontal plane that divides the body or organ into upper and lower portions

what is epithelial tissue and what are its four types

simple is composed of a single layer of cells

stratified is composed of multiple layers of cell

psedostratified appears to be stratified but actually consists of only one layer of cells

transitional can expand and contract

what is the function of connective tissue

It connects the tissues and organs of the body.

The primary protein fibers in the matrix are collagen (for strength), elastin (for flexibility), and reticulum (for support)

what are the functions of skin

Largest organ of the body; it acts like a barrier and protects the body from mechanical impact, variations in temperature, microorganisms, chemicals, and UV radiation from the sun

what are the layers of skin

The surface epidermis, dinner dermis, and subcutaneous hypodermis

what type of tissue comprises the epidermis

It has epithelial cells that lack blood vessels

The outer epidemis is composed of dead cells

what is the difference between endocrine and exocrine glands?

What is the name and function of the sac-shaped structures at the end of the bronchioles?

Name: Alveoli

Function: Sac-shaped structures where gas exchange occurs — oxygen enters the blood and carbon dioxide leaves the blood.

what are sebaceous glands

Glands in the skin that produce oil (sebum) to lubricate and protect the skin and hair

what are eccrine glands

Sweat glands that produce watery sweat to help regulate body temperature by cooling the body

what are apocrine glands

Sweat glands found in areas like the armpits and groin that produce thicker sweat, which can cause body odor when bacteria break it down

what are smooth muscle cells

Muscle cells that work automatically (involuntary) and move substances through organs, such as food in the intestines and blood in vessels.

what are the four common components of neurons and their characteristics

1. Dendrites – Receive incoming signals from other neurons

2. Cell body (soma) – Contains the nucleus; controls the cell

3. Axon – Carries nerve impulses away from the cell body

4. Axon terminals – Release neurotransmitters to send signals to the next cell

Simple HESI tip: Dendrites receive, axons send.

where is the limbic system and what is its function

Location: Located deep inside the brain, between the cerebral cortex and the brainstem.

Function: Controls emotions, behavior, motivation, and memory (especially emotional memories).

what is the autonomic nervous system

The part of the nervous system that controls involuntary body functions, such as heart rate, digestion, breathing, and blood pressure.

what is a reflex arc

The pathway a nerve impulse follows during a reflex, allowing for a quick, automatic response without conscious thought.

what are the two types of hormones and how are they different

1. Steroid hormones – Made from cholesterol; can enter cells directly to affect DNA and protein production.

2. Non-steroid hormones – Made from proteins or amino acids; bind to receptors on the cell surface to trigger a response inside the cell.

Simple difference: Steroid = go inside the cell, Non-steroid = act on the outside.

what is the pituitary gland

A small gland at the base of the brain that controls other endocrine glands and regulates growth, metabolism, and reproduction

what is the thymus gland

A gland behind the sternum that helps develop T-cells, which are important for the immune system

what is the pineal gland’s responsibility

A small gland in the brain that produces melatonin to regulate sleep-wake cycles

what are thyroxine and calcitonin and from what gland are they released

Thyroxine (T4):

• Function: Regulates metabolism, growth, and development

• Gland: Thyroid gland

Calcitonin:

• Function: Lowers blood calcium by helping calcium enter bones

• Gland: Thyroid gland

HESI tip: Both from thyroid; thyroxine speeds up, calcitonin puts calcium in bones.

what are the parathyroid glands

Small glands behind the thyroid that regulate blood calcium levels by releasing parathyroid hormone (PTH)

what are capillaries and what are their three types

Capillaries:
The smallest blood vessels where exchange of oxygen, nutrients, and waste occurs between blood and tissues.

Three types of capillaries:

1. Continuous capillaries – Have tight walls, allow only small molecules to pass

2. Fenestrated capillaries – Have pores, allow larger molecules and fluids to pass

3. Sinusoidal capillaries – Large gaps, allow blood cells and proteins to pass

HESI tip: Continuous = tight, Fenestrated = small holes, Sinusoidal = big gaps.

what is blood and what is its composition

Blood:
A fluid that circulates through the body, transporting oxygen, nutrients, hormones, and waste.

Composition of blood:

1. Plasma – the liquid part, carries nutrients, hormones, and waste

2. Red blood cells (erythrocytes) – carry oxygen

3. White blood cells (leukocytes) – fight infection

4. Platelets (thrombocytes) – help with clotting

HESI tip: Plasma = liquid, RBC = oxygen, WBC = defense, Platelets = clotting.

what are erythrocytes (red blood cells)

Blood cells that carry oxygen from the lungs to the body and bring carbon dioxide back to the lungs

what are leukocytes (white blood cells)

Blood cells that fight infections and help the immune system

what are the AV valves

Valves between the atria and ventricles of the heart that prevent blood from flowing backward when the ventricles contract.

• Right AV valve = Tricuspid

• Left AV valve = Mitral (Bicuspid)

what is the function of the sinuses

Air-filled spaces in the skull and face that lighten the skull, produce mucus, and help warm and humidify air

how do ligaments and tendons differ

Ligaments: Connect bone to bone and stabilize joints.
Tendons: Connect muscle to bone and help move the skeleton

how is breathing controlled?

Breathing is controlled by the brainstem, specifically the medulla oblongata and pons, which monitor carbon dioxide and oxygen levels in the blood and adjust the rate and depth of breathing automatically

where is the duodenum and what is its function

Location: The first part of the small intestine, just after the stomach.

Function: Receives chyme from the stomach and mixes it with bile and pancreatic enzymes to continue digestion.

what is the chief site of fat digestion in the body

The small intestine, where bile from the liver emulsifies fats and pancreatic enzymes break them down

what is a glomerulus and what is its function

A tiny bundle of capillaries in the kidney’s nephron.

Function: Filters blood to form filtrate, removing wastes, water, and small molecules while keeping blood cells and large proteins in the bloodstream.

what is the path of filtrate through the renal tubule

• Bowman’s capsule – collects filtrate from the blood

• Proximal convoluted tubule (PCT) – reabsorbs water, nutrients, and ions

• Loop of Henle – concentrates urine by reabsorbing water and salts

• Distal convoluted tubule (DCT) – fine-tunes ion and pH balance

• Collecting duct – carries urine to the renal pelvis for excretion

what is a zygote

A single cell formed when a sperm fertilizes an egg; it’s the first stage of a developing embryo.

what makes bone resistant to shattering

Collagen gives flexibility, and mineral salts give hardness, together making bones strong but not brittle

the somatic nervous system is responsible for which of the following

Somatic nervous system:
Responsible for voluntary movements of skeletal muscles and sending sensory information to the CNS.

Simple HESI tip: Somatic = voluntary & skeletal muscles

which blood component is chiefly responsible for clotting

Platelets (thrombocytes): Blood cells that help form clots to stop bleeding