Biology Final Semester 2

Four Main Types of Tissue

1. Epithelial Tissue 2. Muscle Tissue 3. Nervous Tissue 4. Connective Tissue

Four Levels of Organization

The four levels of organization in biology are **cells, tissues, organs, and organ systems.**

Cells

basic unit of life

Tissue

groups of cells that work together to perform a specific function

Organs

made up of different types of tissues that work together to perform a specific function

Organ System

groups of organs that work together to perform a specific function for the ortganism

Eleven Body Systems

Circulatory, respiratory, digestive, nervous, endocrine, urinary, lymphatic, immune, integumentary, skeletal, and muscular. Each system has a specific function and works together to maintain homeostasis in the body.

Parts of a Neuron

Cell Body, Dendrites, Axons, Glial Cells, Schwann Cells, Oligodendrocytes, Nodes of Ranvier, Astrocytes (star-shaped cells), Ependymal Cells, Microglia

Cell Body

an enlarged region of the neuron containing the nucleus

Dendrites

extending from the cell body of the neuron are cytoplasmic extensions which receive information and carry it to the cell body

Axons

Long, slender projections of neurons that transmit electrical impulses away from the cell body to other neurons, muscles, or glands

Glial Cells

also known as neuroglia, are non-neuronal cells that provide support and protection to neurons in the nervous system.

Schwann Cells

produce myelin in the PNS

Oligodendrocytes

produce myelin in the CNS

Nodes of Ranvier

small gaps that interrupt the myelin sheath at intervals of 1 to 2 micrometers

Astrocytes

aid the capillaries in the brain in the formation of the blood-brain barrier, which selectively restricts the movement of compounds from the blood in the CNS

Ependymal Cells

ciliated cells that line the cavities of the brain and the central canal of the spinal cord, propel cerebral spinal fluid and regulate the migration of neuroblast

Microglia

aid with immune responses and serve as macrophages to clear away cellular debris, dead cells, and any foreign invaders such as viruses or bacteria

Central Nervous System

The command center of the body that consists of the brain and spinal cord. It controls voluntary and involuntary actions and is responsible for receiving, processing, and sending information throughout the body.

Peripheral Nervous System

The PNS transmits information to and from the CNS and regulates movement and the internal environment. In the PNS, afferent neurons transmit information to the CNS and efferent neurons transmit information away from the CNS. Autonomic Nervous System- sympathetic, parasympathetic, enteric

Primary Endocrine Glands

the pituitary (the master gland), pineal, thyroid, parathyroid, islets of Langerhans, adrenals, ovaries, and testes

Bone Structure

* **Epiphysis-** growing end
* **Diaphysis-** shaft
* **Periosteum-** outside covering
* **Medullary-** inner space containing bone marrow
* **Endosteum-** lining of the medullary cavity

Types of Joints

Some examples include hinge joints, ball-and-socket joints, and pivot joints.

Synarthrosis Joint

a joint that allows no movement ex. Cranial structure

Amphiarthrosis Joint

a joint that allows slight movement ex. vertebra

Diarthrosis Joint

joint that allows free movement in a variety of directions ex. knee, hip, elbow, wrist, and foot

Actin and Myosin

Actin and Myosin are two types of proteins found in muscle fibers. Actin is responsible for generating force during muscle contraction, while Myosin is responsible for converting chemical energy into mechanical work. Together, they form the basis of muscle movement in animals.

Mouth

a chamber for ingestion and initial processing

Esophagus

Muscular contractions of the esophagus (peristalsis) move food to the stomach

Stomach

Acidic breakdown of food occurs in the stomach, **Chyme-** the mixture of partially digested food and gastric juice, Chyme leaves the stomach through the pyloric sphincter to enter the small intestine

Small Intestine

The structure of the small intestine is specialized for digestion and nutrient uptake, Approximately 4.5 meters long (14 ft)

* Duodenum
* Jejunum
* Ileum

The epithelial wall is covered with villi, Each epithelial cell lining the villi is covered by microvilli, Absorbed nutrients move into blood or **lymph capillaries**

Large Intestine

The large intestine, or colon, eliminates waste material, The small intestine empties directly into the large intestine at the cecum, No digestion takes place in the large intestine, and only about 4% of the absorption of fluids by the intestines occurs there, Many bacteria live in and reproduce within the large intestine, and the excess bacteria are incorporated into the feces, Compacted feces pass through the large intestine into the rectum, and then exit the body through the anus

Nose

The external opening of the nose is the **nostrils** or **anterior nares,** The dividing partition between the nostrils is the **nasal septum**, which forms two **nasal cavities,** Each cavity is divided into 3 air passages: **superior, middle, and inferior conchae,** The concae passages lead to the passageway called the **pharynx**. Here, the ear is connected to the sinuses, the ears through the eustacian tubes, and even the eyes through the nasolacrimal ducts, \*\*The palatine (\*\*palate) bones and maxilla (upper jaw bone) separate the nasal cavities from the mouth cavity. **Cilia** (hairs) line the mucous membrane. About 1 qt of mucous is produced daily, The nose has 5 functions:

* It serves as an air passageway
* IT warms and moistens inhaled air
* Its cilia and mucous membrane trap dust, pollen, bacteria, and foreign matter
* It contains olfactory receptors, which smell odors
* It aids in phonation and the quality of voice

Pharynx

The **pharynx** is the correct term for the throat. It is a muscular and membranous tube that is about 5 inches long, extending downward from the base of the skull and eventually becomes the esophagus, The **nasopharynx** is behind the nose; the **oropharynx** is behind the mouth; the **laryngopharynx** is behind the **larynx,** There are 7 openings into the pharynx, In the nasopharynx, there are two openings from the eustachian tubes of the ear, and two openings from the posterior nares of the nose, In the oropharynx is one opening from the mouth, The pharynx also contains 3 pairs of tissues that are part of the lymphatic system:

* The pharyngeal tonsils… the adenoids
* The palatine tonsils
* The lingual tonsils

The pharynx has 3 functions:

* Serves as a passageway for air
* Serves as a passageway for food
* Aids in phonation by changing its shape

Larynx

Commonly called the voicebox, is located at the upper end of the trachea, below the root of the tongue and hyoid bone. It us lined with mucous membrane.The larynx contains vocal chords which produce sound:

* Short, tense vocal cords produce high notes
* Long, relaxed vocal cords produce low notes

We can see several of the cartilage structures of the larynx in a side view:

* The **thyroid cartilage** or Adam’s apple is usually larger in the male, allowing longer vocal cords contributing to a deeper male voice
* The **epiglottis** covers the entrance of the larynx while swallowing, to avoid choking
* The **cricoid** cartilage contains the vocal cords

Trachea

Cartilage rings prevent crushing of the trachea, The passageway for air to and from the lungs. It is lined with cilia (hairs), which sweep foreign matter out of the pathway. It is only about one inch in diameter and 4 1/2 inches long

Bronchi

The **bronchi** are the two main branches at the bottom of the trachea, providing passageway for air to the lungs, Trachea divides into the right bronchus and the left bronchus, and then divides further into the bronchial tree, As the branches of the bronchial tree get smaller, the 2 primary bronchi becomes bronchioles, and then very small **alveolar** ducts, The left bronchus is smaller than the right bronchus, because room is needed to accommodate the heart, If a foreign body is inhaled of aspirated (drawn by suction), it usually lodges in the larger right bronchus or enters the right lung

Lungs

The lungs are two spongy organs located in the thorax, Consist of elastic tissue, filled with an interlacing network of tubes and sacs that carry air and blood vessels that carry blood, Each lung is divided into two lobes, the right lung into 3 lobes and the left lung into 2, The left lung has an indentation called the **cardiac depression** or **notch** for placement of the heart, At the end of each bronchiole are the **alveoli**. The lungs contain about 300 million alveoli sacs, which are air cells where the exchange of oxygen and carbon dioxide takes place with the capillaries, The base of the lungs rest on the **diaphragm, Total Lung Capacity-** is 3.6-9.4 liters in an average male

Blood

Made up of blood cells and plasma

* Blood cells:
* Erythrocytes (red blood cells)
* Leukocytes
* Thrombocytes (platelets)
* Plasma is the fluid portion

Parts of the Heart

The four chambers of the heart are the right and left atria and ventricles. The atria receive blood, while the ventricles pump blood out of the heart. The heart also has four valves that prevent blood from flowing backward.

Blood Vessels

A closed network of tubes

* This includes:
* Arteries
* Capillaries
* Veins


* General Structure:
* Tunica intima
* Tunica media
* Tunica adventitia

Arteries

Blood vessels that carry blood away from the heart are called arteries, They are the thickest blood vessels and they carry blood high in oxygen known as oxygenated blood, Lumen is small, No valve, Repeated branching

Capillaries

The smallest blood vessels are capillaries and they connect the arteries and veins, This is where the exchange of nutrients and gases occurs, Two kinds of Capillaries:

* **Continuous-** skin, lung, smooth muscle, connective tissues
* **Fenestrated-** pancreas, endocrine glands, small intestine, choroid plexus, cilliary process etc

Veins

Blood vessels that carry blood back to the heart are called veins, They have one-way valves which prevent blood from flowing backwards, They carry blood that is high in carbon dioxide known as deoxygenated blood, Thin walled, Large irregular lumen, Have valves, Dead space around

Nephron

Each kidney has about 1.2 million nephrons, Each composed of two principal parts

* **Renal corpuscle-** filters the blood plasma, consists of the glomerulus and a two layerd glomerular (Bowman) capsule that encloses glomerulus
* **Renal tubule-** long coiled tube that converts the filtrate into urine
* **Perietal layer of bowman capsule** is simple squamous epithelium
* **Visceral layer of Bowman capsule** consists of elaborate cells called **podocytes** that wrap around the capillaries of the glomerulus
* **Capsular Space** separates the two layers of Bowman Capsule

Parts of the Urinary System

This organ system is responsible for filtering waste products from the blood and eliminating them from the body. It consists of the kidneys, ureters, bladder, and urethra.

Kidneys

Organ responsible for filtering waste products and excess fluids from the blood, regulating blood pressure, producing hormones that control red blood cell production and vitamin D activation.

Ureters

muscular tubes that transport urine from the kidneys to the bladder. They are about 10-12 inches long and are lined with smooth muscle that contracts to push urine down to the bladder. Ureters play a crucial role in maintaining the body's fluid balance and eliminating waste products.

Bladder

**Urinary Bladder-** muscular sac located on floor of pelvic cavity; inferior to peritoneum and posterior to pubic symohysis, Three layers:

* Parietal peritoneum, superiorly, fibrous adventitia other areas
* Muscluaris: detrusor muscle: three layers of smooth muscle
* Mucosa: transitional epithelium
* **Rugae-** conspicuous wrinkles in relaxed bladder


* **Trigone-** smooth-surfaced triangular area marked with openings of ureters and urethra

Urethra

the duct by which urine is conveyed out of the body from the bladder

Lymphatic Vessels

**Lymphatic Capillaries-** tiny vessels found in the tissues of most organs in your body which transport and filter lymph from body cells and tissues; smallest, **Lymphatic Collecting Vessels-** next largest, similar to venules, **Lymphatic Trunks-** similar to veins; any large lymph vessels that forms from the convergence of smaller lymph vessel, **Lymphatic Ducts-** biggest; drain into subclavian vein

Thymus

makes white blood cells, called lymphocytes, which protect the body against infections

Lymph Nodes

Bean-shaped bodies, With afferent vessels (entering at the periphery) and efferent lymph vessels (emerging at the hilus), Arranged in groups, along the blood vessels or the flexural side of the joint, Divided into superficial and deep groups

Spleen

\
Located in the left epigastric region between the 9th and 11th rib (in line with the 10th rib), Largest lymphatic organ in the body, Can vary considerably in size and weigh, Controls the level of red blood cells, white blood cells, and platelets

Tonsils

Clusters of lymphatic cells and extracellular matrix not completely surrounded by a connective tissue capsule, Consist of multiple germinal centers and crypts, Several groups of tonsils form a protective ring around the pharynx

* **Pharyngeal tonsils (or adenoids)** in nasopharynx
* **Palatine tonsils** in oral cavity
* **Lingual tonsils** along posterior one-third of the tongue

Uterus

a hollow, muscular, pear-shaped organ about the size of a woman;s clenched fist, The top is tipped forward in a normal **“anteflexion”** position, It can be divided into the body or corpus above the **fallopian tubes** called the **fundus,** The uterus is supported and held in position by a number of ligaments

* **Uterus wall has three layers:**
* Outside layer- called the **perimetrium**
* Muscular inside layer- **myometrium**
* Mucous membrane lining- **endometrium**
* **Three main functions:**
* The endometrium sheds the lining of the uterus every 21-40 days by menstruation
* Provides a place for the protection and nourishment of the fetus during pregnancy
* It contracts during labor to expel the fetus

Fallopian Tubes

4-6 inches long, The egg, released from the ovary, captured by the **fimbria** and brought into the fallopian tube. The egg is moved along inside the tube by muscular contractions and the waving action of cilia, It takes an egg about 3-4 days to travel the length of the tube, If the egg is fertilized, it happens in the fallopian tubes

Ovaries

The two ovaries are attached to each side of the uterus by a ligament, They are oval shaped, about the size of a large olive, and lie close to the fimbria at the end of the fallopian tubes, Each ovary is filled (already at birth) with egg containing sacs called **follicles,** Each egg is called an **ovum, Ovulation-** once every 28 days, one follicle in one ovary ripens. This mature follicle is a **graafian follicle.** the follicle ruptures in response to hormones from the pituitary gland, releasing the ovum. After the follicle ruptures, it becomes a mass of yellow cells called the **corpus luteum** (temporary progesterone-producing structure)

Vagina

Extends from the cervix to the outside of the body, 3 1/2 inch long muscular tube that expands in length and width during arousal, Female organ for copulation, receiving the seminal fluid from the male. It is also a passageway for menstruation of the birth of the fetus

Vulva

5 organs making up external:

* **Mons pubis-** triangular-shaped pad of fatty tissue over the pubis bone, covered with hair
* **Labia majora-** 2 large folds of adipose tissue on sides of opening
* **Labia minora-** 2 smaller folds of adipose tissue on the inside of labia majora
* **Vestibule-** area between labia with openings for the vagina, urethra, and two excretory ducts for Bartholin’s glands (lubricant)
* **Clitoris-** sensitive fold of tissue partially covered by hood

Breasts

Mammary glands, varying in size according to age, heredity and the amount of fatty tissue present, Each breast has 15-20 glandular lobes separated by connective tissue, After childbirth, the pituitary gland stimulates these lobules with prolactin and they produce milk, Dark-colored circle at the tip of the breast is called the **areola-** contains sebaceous glands to keep the skin conditioned, In the center is the nipple, where the ducts from the lobules open, The first secretion is not true milk, but a thin yellowish substance called **colostrum-** contains nutrients and the mother’s immunities (secondary immunity) that can protect the baby

Zygote

a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum

Fetus

an offspring of a human or other mammal in the stages of prenatal development that follow the embryo stage (in humans taken as beginning eight weeks after conception)

Embryo

an unborn or unhatched offspring in the process of development, in particular a human offspring during the period from approximately the second to the eighth week after fertilization (after which it is usually termed a fetus)

Life Stages

Growth and development begins at birth and ends at death

* **Infancy-** birth to 2 year
* **Early Childhood-** 2-6 years
* \*\*Late Childhood-\*\*6-12 years
* **Adolescence-** 12-20 years
* **Early Adulthood-** 20-40 years
* **Middle Adulthood-** 40-65 years
* **Late Adulthood-** 65+ years